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Our Top Recommended Big Brake Upgrade Kits For Your Audi S2
There were around 2,000 Audi S2s registered in the UK by the end of production. The B3 Coupe chassis, the 2.2 litre 5-cylinder turbo and permanent quattro were never a volume formula, and the ones still running in 2026 tend to be in good hands. The engine responds well to work and the drivetrain absorbs power at a rate the brakes often can’t keep pace with. That is usually how the call to us starts.
This page covers the eight HiSpec kits listed for the S2. Tarox make no kit for this car, so it is all HiSpec, made to order in Dartford. Three things worth knowing before you scroll: Monster calipers are available at 16 inch on the S2, which is not typical in this catalogue and means an S2 on standard alloys already has access to the Monster range. The braided hose situation splits by caliper family, which we explain in the box section. And there is a title on one listing that reads ‘Audi A2-S2’, which has nothing to do with the modern Audi A2 hatchback; it is explained at pick 3. The full S2 brake range is on the site if you want the raw listing.
- HiSpec only: Tarox make no kit for the S2. All eight kits are from HiSpec Motorsport, made to order in Dartford, up to 28 working days, five caliper colours
- Monster calipers clear 16 inch on the S2: both the 315mm Monster 4 and 314mm Monster 6 are confirmed at 16 inch minimum from HiSpec's own listing text
- Pads are priced separately on all eight kits. Monster kits include braided hoses; the two Billet 4 kits price hoses as an optional extra
- The 360mm Monster 4 lists at £1,635 inc VAT, which is £15 less than the 335mm Monster 4 at £1,650. Both flagged in the compare table
HiSpec Motorsport and the S2
Tarox list no kit for the Audi S2. The full range here is HiSpec Motorsport, machined in Dartford from 6082 T6 billet aluminium with calipers and pistons both from the same material. Every kit is made to order in up to 28 working days, with the calipers finished in your choice of black, red, blue, gold or silver. Pads are priced separately across the range so you choose the compound for how the car is used.
One thing specific to the S2 catalogue: the disc vane design changes at the 335mm threshold. The 314mm and 315mm kits run straight vane discs; the 335mm and 360mm kits use curved vane rotors. Curved vane discs pull more air across the rotor face at high rotation speeds and manage heat better under track conditions. It is worth knowing when comparing a 315mm Monster kit against the 335mm Monster, because the price difference buys a disc that handles sustained heat loading differently, not just a bigger rotor.
Billet 4 caliper
HiSpec's four-piston road caliper with external boots to keep grit out of the seals. Available at 314mm and 325mm on the S2. Braided hoses are an optional extra on both Billet 4 kits. The starting point for an S2 on standard alloys or on a budget.
Monster 4 and Monster 6
Larger pistons and a longer pad than the Billet 4 for more clamp force and a firmer pedal, with high temperature seals and stainless steel wear plates. Monster kits include braided hoses in the box. Available at 314mm, 315mm, 335mm and 360mm on the S2.
Wheel sizes
HiSpec publish the minimum wheel size in the listing text for every kit on this page. The table below lists those figures directly. Diameter is the easy half of the question: a 16 inch wheel clears the caliper radially, a 15 inch one does not. Depth is the part specific to your wheels, how far the spoke profile extends inward behind the rim, and whether it clears the caliper body under full lock. A 17 inch wheel of the right diameter can still foul on a shallow-spoke profile. Give Cameron the make, model and offset of your wheels before ordering and he will check. Tarox also publish a clearance template if you want to do the measure yourself first.
| Kit | Disc | Smallest wheel |
|---|---|---|
| HiSpec 314mm Billet 4 | 314mm | 16 inch |
| HiSpec 315mm Monster 4 | 315mm | 16 inch |
| HiSpec 314mm Monster 6 | 314mm | 16 inch |
| HiSpec 325mm Billet 4 | 325mm | 17 inch |
| HiSpec 335mm Monster 4 | 335mm | 17 inch |
| HiSpec 335mm Monster 6 | 335mm | 17 inch |
| HiSpec 360mm Monster 4 | 360mm | 18 inch |
| HiSpec 360mm Monster 6 | 360mm | 18 inch |
314mm Billet 4: the 16 inch entry kit
The 314mm Billet 4 is the entry point for an S2 on standard 16 inch alloys. At £1,130 inc VAT it is the cheapest kit in the catalogue and a solid step over the standard single-piston sliding calipers. The Billet 4 carries four radial pistons with external boots keeping road grit away from the seals, paired with straight vane two-piece discs. It is not the biggest or most aggressive kit here, but on a road car in standard trim or with light modification it is the right starting place.
Two things to budget for: pads are priced separately, and the braided hoses on this kit are an optional extra. Both are worth adding when you order so the kit is fully specced when it arrives. The caliper is available in black, red, blue, gold or silver.
- £1,130.00 inc VAT
- Clears 16 inch wheels
- 314mm straight vane two-piece discs
- Four-piston Billet 4 caliper, made to order in Dartford
- Pads and braided hoses priced separately
Monster calipers at 16 inch: 315mm Monster 4 and 314mm Monster 6
On most cars in this guide series, stepping to the Monster caliper means stepping to 17 inch wheels. The S2 is one of the exceptions. Both the 315mm Monster 4 and the 314mm Monster 6 are confirmed at 16 inch minimum from HiSpec’s own listing text. That opens up the Monster caliper to any S2 owner already on 16s, which covers most standard cars.
The Monster caliper runs a pad one third longer than the Billet 4, which gives more contact area and more clamp force. The Monster 6 adds two pistons over the Monster 4, trading a higher price (£1,683 vs £1,365 inc VAT) for more pedal feel and a firmer bite. Both include braided hoses in the box. Both use straight vane discs at this size. On a road S2 doing occasional track days, the Monster 4 at 315mm is Garreth’s pick in this bracket; the Monster 6 suits a car making more power or doing sustained circuit work.
- Monster 4 at £1,365.00 inc VAT, Monster 6 at £1,683.00 inc VAT
- Both clear 16 inch wheels (confirmed from HiSpec listing text)
- Monster 4: 315mm straight vane discs; Monster 6: 314mm straight vane discs
- Braided hoses included in both Monster kits
- Pads priced separately on both; choose the compound to match how the car is used
325mm Billet 4: the step to 17 inch
The 325mm Billet 4 is where the 17 inch threshold starts. At £1,470 inc VAT it sits above the 315mm Monster 4 in price while staying in the Billet 4 caliper family: four pistons, external boot seals, the standard Billet 4 spec. If the car is already on 17 inch alloys and the Billet 4 suits the build, this is the kit to look at before stepping to the Monster range.
One thing to note on this listing: the product title reads ‘Audi A2-S2 325mm Billet 4’. The modern Audi A2 is a completely different car (a lightweight aluminium hatchback from 1999 to 2005) and has no connection to this kit. The ‘A2’ reference in the title is a legacy Audi platform designation from the S2’s era, not the modern hatchback. This kit is built for the S2 and is in the correct category. If you are an Audi A2 owner who landed here by searching, this kit will not fit your car. Ring Cameron with your registration if there is any doubt before ordering. Braided hoses are an optional extra on this kit, same as the 314mm Billet 4.
- £1,470.00 inc VAT
- Clears 17 inch wheels
- 325mm straight vane two-piece discs
- Four-piston Billet 4 caliper, made to order in Dartford
- Pads and braided hoses priced separately; note the A2-S2 title (see above)
335mm Monster 4 and Monster 6: the track build
Once the S2 is on 17s and doing regular circuit work, these are the two kits to look at. The 335mm disc is a proper step from the 315mm and 325mm options, and from here the discs switch from straight vane to curved vane rotors, which pull more air across the face at higher rotation speeds. Both kits include braided hoses in the box; pads are still priced separately.
Monster 4 at £1,650 inc VAT, Monster 6 at £1,773. Same pad size on both, but the six-pot version has up to 63 per cent more piston area. On a 220bhp road S2 the Monster 4 is the natural call; the Monster 6 is for a car with a significant engine build or that does more than occasional circuit days. Two pricing notes: the 360mm Monster 4 in the 18 inch section below lists at £1,635, which is £15 less than this 335mm Monster 4. That is flagged in the compare table. And the Garreth and Cameron default on a modified S2 going to track days on 17s is the 335mm Monster 4, not the 360mm, because the disc size is proportionate to what the car is.
- Monster 4 at £1,650.00 inc VAT, Monster 6 at £1,773.00 inc VAT
- Both clear 17 inch wheels
- 335mm curved vane two-piece discs on both kits
- Braided hoses included; pads priced separately
- High temperature seals and stainless steel wear plates on both Monster calipers
On 18 inch wheels
The two 360mm kits sit at the top of the range and need 18 inch wheels to clear the caliper. Both use curved vane rotors and include braided hoses in the box. The Monster 4 at £1,635 and the Monster 6 at £1,863. One thing to flag: the 360mm Monster 4 lists at £1,635, which is £15 below the 335mm Monster 4 at £1,650 despite being a larger disc. The price does not follow the disc size at this end of the catalogue. If the car is genuinely on 18s and doing track work, these are the kits; if it is on 17s, the 335mm Monster 4 remains the value pick. Garreth’s view is that at S2 power levels, the 335mm Monster is where the kit and the car are matched. The 360mm suits a more heavily modified car.
Pads are priced separately on both kits.
What is in each box
The box contents split by caliper family on the S2, and it is worth knowing before you budget. The two Billet 4 kits (314mm and 325mm) include the calipers, two-piece discs, bracket set and brake fluid. Braided hoses are an optional extra on both: they are not in the standard box but can be added when you order. The six Monster kits (315mm, 314mm, 335mm and 360mm in both four-piston and six-piston) include braided hoses as standard. Pads are priced separately across all eight kits regardless of caliper family, so you choose the compound to match how the car is driven.
HiSpec make the kits to order in Dartford. Lead time is up to 28 working days from order. If you are working to a specific date, ring when you order and Cameron will give you the current build queue picture. Calipers are available in black, red, blue, gold or silver at no extra cost.
| In the box | Billet 4 (314mm, 325mm) | Monster 4 and 6 (all sizes) |
|---|---|---|
| Calipers | Billet 4, 4-piston, 6082 T6 billet alloy | Monster 4 or Monster 6, 4 or 6-piston, 6082 T6 billet alloy |
| Discs | Two-piece, straight vane | Two-piece, curved vane (335mm+) |
| Brackets and hardware | Included | Included |
| Braided hoses | Optional extra | Included |
| Pads | Priced separately | Priced separately |
| Brake fluid | DOT 5.1 included | DOT 5.1 included |
| Caliper finish | Black, red, blue, gold or silver | Black, red, blue, gold or silver |
| Made in | Dartford, UK, up to 28 working days | Dartford, UK, up to 28 working days |
Every kit on this page compared
| Kit | Disc | Caliper | Disc type | Smallest wheel | Hoses | Price inc VAT |
|---|---|---|---|---|---|---|
| HiSpec 314mm Billet 4 | 314mm | 4 piston | Straight vane | 16in | Optional extra | £1,130.00 |
| HiSpec 315mm Monster 4 | 315mm | 4 piston | Straight vane | 16in | Included | £1,365.00 |
| HiSpec 314mm Monster 6 | 314mm | 6 piston | Straight vane | 16in | Included | £1,683.00 |
| HiSpec 325mm Billet 4 | 325mm | 4 piston | Straight vane | 17in | Optional extra | £1,470.00 |
| HiSpec 335mm Monster 4 | 335mm | 4 piston | Curved vane | 17in | Included | £1,650.00 |
| HiSpec 335mm Monster 6 | 335mm | 6 piston | Curved vane | 17in | Included | £1,773.00 |
| HiSpec 360mm Monster 4 | 360mm | 4 piston | Curved vane | 18in | Included | £1,635.00 less than 335mm Monster 4 |
| HiSpec 360mm Monster 6 | 360mm | 6 piston | Curved vane | 18in | Included | £1,863.00 |
Prices include VAT and were correct on 11 September 2026. Note: the 360mm Monster 4 lists below the 335mm Monster 4 despite being a larger disc. Wheel sizes confirmed from HiSpec’s published listing text for each kit. Pads are priced separately on all eight kits.
Common questions
Why does the 360mm Monster 4 cost less than the 335mm Monster 4?
At £1,635 the 360mm Monster 4 is £15 cheaper than the 335mm Monster 4 at £1,650, despite being a bigger disc. Both use the same Monster 4 four-piston caliper. The gap sits in HiSpec's pricing structure rather than any spec difference that explains it. We flag it because it catches people out when they are comparing the two. On a 17 inch car, the 335mm Monster 4 remains the better proportioned kit for the car. The 360mm needs 18 inch wheels to clear, so the 360mm is only the right pick if the car is already on 18s.
What does "A2-S2" mean on the 325mm Billet 4 listing?
It is a legacy Audi platform designation, not a reference to the modern Audi A2 hatchback. The modern Audi A2 is a small aluminium city car built from 1999 to 2005 and has no connection to this kit. The Audi S2 was built on the B3 Coupe platform from 1990 to 1995, and 'A2' in the listing title reflects how HiSpec originally coded the platform in their catalogue. This kit is in the Audi S2 brake category and is built for the S2. If you own an Audi A2 hatchback, this kit will not fit your car. Ring us with your registration if there is any doubt and Cameron will confirm before anything goes to build.
Will the Monster kits fit behind my 16 inch standard alloys?
Yes, if you are on the 315mm Monster 4 or the 314mm Monster 6. Both kits state 16 inch minimum in the HiSpec listing text. The diameter question is settled; the part that requires a check is spoke depth. HiSpec calipers are wider than the standard sliding caliper, and whether a specific 16 inch wheel's spoke profile clears the body under full lock depends on the wheel design. Give Cameron the make and model of your wheels alongside the size and he will check before anything is ordered. Standard Audi S2 alloys should clear, but aftermarket 16s vary.
How long before a HiSpec kit arrives?
HiSpec make every kit to order in Dartford. The quoted lead time is up to 28 working days from order confirmation. If you are working to a specific track day date or a deadline, tell us when you ring and Cameron will give you the current build queue picture so you know exactly where the timeline sits.
Will these work with ABS and the S2 quattro drivetrain?
HiSpec state the kits are designed for direct replacement on the standard front hubs. The front braking circuit operates independently of the quattro drivetrain, and the ABS sensor mounts stay in the standard position. If your S2 has been modified in a way that changes the front hub geometry, tell us when you order and we will confirm the fitment with HiSpec before the kit goes to build.
What we would actually fit
On a standard S2 with 16 inch alloys and no specific reason to go further: the 315mm Monster 4 at £1,365. The Monster caliper clears the 16 inch wheel and the kit arrives with hoses already in the box. It is a proper step from the standard setup, proportionate to what the car is, and there is nothing left to source once it lands. If the budget is the constraint or the car is genuinely standard, drop back to the 314mm Billet 4 at £1,130. Same wheel clearance, lower price, right caliper for the application, just budget separately for pads and hoses.
For a 17 inch car with modification behind it: the 335mm Monster 4. Garreth’s default for a remapped S2 or one that does track days. The curved vane discs manage heat better than the straight vane sets below, the kit arrives with hoses included, and the price sits in the right place for what you are getting. The 360mm Monster options need 18s and are for the more heavily modified end; on a typical S2 they are a size ahead of what the car needs.
If you are between two of these, ring us on 0115 9893488 with your wheel spec and what the car does at weekends. Cameron handles the wheel clearance side: have the make and model of your alloys handy and he will confirm what fits before anything goes to build.