Our Top Recommended Big Brake Upgrade Kits For Your Opel Calibra
The first question on a Calibra is not disc size. It is stud count. Standard models, the 2.0 16v, 2.5 V6 and C20LET variants, all sit on a 4-stud front hub. The Turbo 4×4 runs 5-stud. Tarox split their kits to match: pick the wrong bracket and the kit does not go on. HiSpec do not split by stud count, so their listings work across every Calibra variant without needing to check.
There is also a pricing oddity in the Tarox range worth flagging before you start. The 308mm 4-stud Sport kit costs £2,092 inc VAT. The 318mm 4-stud Sport kit costs £2,020. The bigger disc is £72 cheaper. Cameron flags this on every Calibra enquiry. The 330mm flagship is 5-stud only, which means 4-stud owners top out at the 318mm on Tarox. The full Calibra range is on the site if you want to browse it first.
- HiSpec list the Calibra as Vauxhall Calibra. Tarox list it as Opel Calibra. Same car, different badges on the listing.
- Standard Calibra models (2.0 16v, 2.5 V6, C20LET) run a 4-stud front hub. Turbo 4x4 runs 5-stud.
- HiSpec kits fit all Calibra variants. Tarox kits are sold in 4-stud and 5-stud versions separately.
- The Tarox 308mm 4-stud costs more than the 318mm 4-stud. The 308mm is the kit to skip.
- HiSpec kits need pads and braided hoses ordered separately. Tarox include both in the box.
HiSpec and Tarox on the Calibra
Both brands list the Calibra and both have covered it long enough that the brackets are proven. The key difference is how they handle the 4-stud and 5-stud split.
HiSpec Motorsport
UK-made in Llanelli, South Wales. HiSpec support the Calibra across six disc sizes from 300mm to 360mm in the road range, and a further six in R132 competition spec. They make one kit per disc size that covers all hub patterns. Pads and braided hoses are sold alongside at checkout.
Tarox
Italian manufacturer. Tarox cover the Calibra from 305mm to 330mm across separate 4-stud and 5-stud versions. The bracket geometry is Calibra-specific. Vehicle-specific braided hoses and a Corsa pad are pre-installed in every kit. Cameron will tell you which bracket version to order before anything goes to build.
Stud count matters here
The Calibra is one of the few cars where stud pattern changes what you can order. Standard cars run 4-stud front hubs. The Turbo 4x4 runs 5-stud. HiSpec sell one part number for all variants. Tarox label each kit explicitly and the brackets are not interchangeable.
Minimum wheel sizes
Minimum wheel size is a property of the disc and caliper, not the car. These figures hold across every Calibra variant. Depth (spoke to disc face) is the car-specific check and Cameron confirms that before ordering if your wheels are borderline.
| Kit | Disc | Hub | Min wheel |
|---|---|---|---|
| HiSpec Billet 4 | 300mm | All variants | 16 inch |
| Tarox 305mm Sport | 305mm | 4-stud or 5-stud (order separately) | 16 inch |
| Tarox 308mm Sport | 308mm | 4-stud only | 17 inch |
| HiSpec Monster 4 | 325mm | All variants | 17 inch |
| HiSpec Monster 6 | 325mm | All variants | 17 inch |
| Tarox 318mm Sport | 318mm | 4-stud or 5-stud (order separately) | 17 inch |
| HiSpec Monster 6 | 335mm | All variants | 17 inch |
| Tarox 330mm Sport | 330mm | 5-stud Turbo 4x4 only | 17 inch |
| HiSpec Monster 4 | 360mm | All variants | 18 inch |
| HiSpec Monster 6 | 360mm | All variants | 18 inch |
Start on 16s: HiSpec 300mm Billet 4
The Billet 4 is the entry point for the Calibra upgrade and the only HiSpec road kit that clears a standard 16 inch wheel. A 300mm two-piece floating disc and 4-piston alloy caliper replace the standard unit. One part number fits all hub patterns including the Turbo 4×4.
The Monster 4 at 325mm costs £1,596 inc. That is £132 more for a larger disc and a caliper built to run hotter. If the car is heading to 17 inch wheels at any point, Cameron would skip the Billet 4 and go straight to the Monster 4. But if the wheels are staying at 16 inch, the Billet 4 is the honest call.
- 300mm two-piece floating disc
- 4-piston alloy caliper
- Fits all Calibra variants, 4-stud and 5-stud
- 16 inch minimum
- Pads and braided hoses ordered separately
Tarox on 16s: 305mm Sport
The Tarox 305mm is the only Tarox kit that clears a 16 inch wheel. At £1,860.66 inc VAT it is £396 more than the HiSpec Billet 4 for 5mm more disc, a 6-piston caliper, vehicle-specific braided hoses already plumbed, and Corsa pads pre-installed. The Tarox box arrives ready to fit.
Two listings exist: one for the 4-stud hub and one for 5-stud. The caliper and disc are identical. The bracket changes. Cameron confirms which version fits your car before anything goes to order. Both cost the same.
- 305mm two-piece floating disc
- 6-piston caliper
- 4-stud and 5-stud versions sold separately
- 16 inch minimum
- Vehicle-specific braided hoses and Corsa pads included
Most Calibras end up here: HiSpec 325mm Monster 4
The Monster 4 is the kit Garreth points most Calibra owners toward. A 325mm disc with 4-piston Monster caliper on a car that has moved to 17 inch wheels. The Monster caliper is built to handle sustained heat better than the Billet unit, which matters on any Calibra that actually gets used.
The Monster 6 at £1,683 inc VAT is the same 325mm disc with a 6-piston caliper. The extra two pistons are worth having if the car sees occasional track days. For a road car that stays on the road, the Monster 4 at £1,596 does the job cleanly and Cameron would not push you to spend the extra £87 unless the use case justified it.
- 325mm two-piece floating disc
- Monster 4 (4-piston) or Monster 6 (6-piston) caliper
- Fits all Calibra variants, 4-stud and 5-stud
- 17 inch minimum
- Pads and braided hoses ordered separately
Track-biased: HiSpec 335mm Monster 6
The 335mm Monster 6 is the pick for a Calibra used regularly on track. Ten more millimetres over the 325mm kit and a 6-piston caliper that keeps working through a full session without fade. It still clears a 17 inch wheel, so nothing changes at the axle except the brake.
The price is £1,773 inc VAT. That is £90 more than the 325mm Monster 6 and £177 more than the 325mm Monster 4. On a car that gets driven properly rather than used for occasional trackdays, the 335mm is the honest stopping point before the 360mm on 18s becomes relevant.
- 335mm two-piece floating disc
- 6-piston Monster caliper
- Fits all Calibra variants, 4-stud and 5-stud
- 17 inch minimum
- Pads and braided hoses ordered separately
Turbo 4x4 flagship: Tarox 330mm 5-stud
The 330mm is Tarox’s largest Calibra kit and it is 5-stud only. The Turbo 4×4 runs a wider front hub than the standard car, and the bracket geometry for the 330mm was engineered for that pattern. On a 4-stud Calibra, this kit does not exist.
For Turbo 4×4 owners looking for the full Tarox spec, the 330mm gives a 6-piston caliper, Calibra-specific braided hoses and a Corsa pad in one box at £2,280 inc VAT. Standard 4-stud owners who want to push into the Tarox range further than the 305mm have the 318mm at £2,020 as their ceiling, with the same 6-piston caliper and the same box contents.
- 330mm two-piece floating disc
- 6-piston caliper
- 5-stud Turbo 4x4 only
- 17 inch minimum
- Vehicle-specific braided hoses and Corsa pads included
On 18 inch wheels
HiSpec cover the Calibra up to 360mm for cars running 18 inch wheels. The 360mm Monster 4 is £1,780.50 inc VAT and the Monster 6 is £1,863. Both fit all Calibra hub patterns. There is no Tarox kit at 360mm for the Calibra.
What is in the box
The main practical difference between HiSpec and Tarox on this car is what arrives in the box and what you need to order alongside.
HiSpec: caliper, brackets and discs
Every HiSpec kit includes the caliper, vehicle-specific brackets, two-piece floating discs and flexi hose hardware. Pads and braided hoses are priced separately at checkout. Cameron can advise on pad compound based on what the car does: EBC Greenstuff for a road car, Yellowstuff if it sees occasional track days, or a full track compound for regular circuit use.
Tarox: complete kit including pads and hoses
Every Tarox kit includes the caliper, vehicle-specific brackets, two-piece floating discs, a Corsa pad set pre-installed, and vehicle-specific braided hoses. The Corsa is a medium-friction compound that works on the road and covers most club trackdays without needing to swap pads. Everything to install arrives in one box.
Every kit compared
All kits listed below are published and verified at time of writing. Prices are inc VAT. The Tarox 308mm is included for completeness but flagged as a skip on pricing grounds.
| Kit | Disc | Hub | Min wheel | Price inc VAT | Pads |
|---|---|---|---|---|---|
| HiSpec Billet 4 | 300mm | All variants | 16in | £1,464 | Extra |
| Tarox 305mm Sport | 305mm | 4-stud | 16in | £1,861 | Included |
| Tarox 305mm Sport | 305mm | 5-stud | 16in | £1,861 | Included |
| HiSpec Monster 4 | 325mm | All variants | 17in | £1,596 | Extra |
| HiSpec Monster 6 | 325mm | All variants | 17in | £1,683 | Extra |
| Tarox 318mm Sport | 318mm | 4-stud | 17in | £2,020 | Included |
| Tarox 318mm Sport | 318mm | 5-stud | 17in | £2,020 | Included |
| HiSpec Monster 6 | 335mm | All variants | 17in | £1,773 | Extra |
| Tarox 330mm Sport | 330mm | 5-stud only | 17in | £2,280 | Included |
| HiSpec Monster 4 | 360mm | All variants | 18in | £1,781 | Extra |
| HiSpec Monster 6 | 360mm | All variants | 18in | £1,863 | Extra |
| Tarox 308mm Sport skip | 308mm | 4-stud only | 17in | £2,092 | Included |
HiSpec R132: club and competition use
The R132 is HiSpec’s racing caliper range. It is designed for cars running slick tyres with a proper brake bias setup, hillclimb work and circuit use. The R132 costs less than the Monster series at an equivalent disc size: the 315mm R132-4 is £1,099.50 compared to £1,596 for the 325mm Monster 4. The lower price reflects a different design brief, not a cheaper product.
Minimum wheel clearance for R132 calipers is not published in the standard catalogue. Call Cameron on 0115 647 8650 with your wheel specification before committing to an R132 kit. He will confirm clearance before anything is ordered.
Common questions
My Calibra is on 15 inch wheels. Does anything on this page fit?
No. The smallest kit on this page is the HiSpec 300mm Billet 4, which needs a 16 inch minimum. If the car is staying on 15s, a brake upgrade is not possible from this range. Changing wheels to 16 inch would be the first step.
How do I check if my Calibra is 4-stud or 5-stud?
Count the wheel bolts on one front wheel. Four bolts means 4-stud. Five bolts means 5-stud. Standard Calibra models are 4-stud. The Turbo 4x4 is 5-stud. If you are ordering a Tarox kit, Cameron confirms the hub pattern before the order goes in.
Why does the Tarox 308mm cost more than the 318mm?
The 308mm 4-stud kit is priced at £2,092 inc VAT. The 318mm 4-stud kit is £2,020. There is no published explanation for the higher price on the smaller disc. Our advice is straightforward: buy the 318mm. You get a larger disc for less money. The same 6-piston caliper appears in both kits and both include braided hoses and a Corsa pad.
Will the HiSpec kits fit the Turbo 4x4 as well as the standard car?
Yes. HiSpec make one part number per disc size that fits both 4-stud and 5-stud hubs. You do not need to specify your hub pattern when ordering HiSpec kits.
Do I need to change my pads when fitting a HiSpec kit?
HiSpec kits do not include pads. If your existing pads are worn, order fresh pads at checkout. Cameron recommends EBC Greenstuff for a road car kept on standard use, Yellowstuff for a car that sees occasional trackdays, and will advise on full track compounds for circuit-focused builds.
What is the difference between Monster 4 and Monster 6?
Both use the same disc size. The Monster 6 has a 6-piston caliper where the Monster 4 has 4 pistons. More pistons distribute clamping force more evenly across a larger pad face. On a road car the difference is small. On a track car the Monster 6 holds up better through sustained heat.
What we would actually fit
On a standard 4-stud Calibra keeping its 16s, the HiSpec 300mm Billet 4, and not a lot of thought required. On a car moving to 17 inch wheels, the Monster 4 at £1,596 is Garreth’s default answer. The £132 gap between 300mm and 325mm makes no sense to cross twice, so if 17 inch wheels are on the plan at all, go there in one step.
For a car used on track, the 335mm Monster 6 at £1,773 is where Cameron stops the conversation on HiSpec road kits. It clears a 17 inch wheel, uses the 6-piston caliper, and the extra 10mm over the 325mm earns its keep through a proper track day. The Monster 4 at 325mm is fine for an occasional track outing. The Monster 6 at 335mm is built the other way around.
Tarox owners on a 5-stud Turbo 4×4 get the 330mm flagship at £2,280 with hoses and pads in the box. 4-stud owners who want Tarox at the top end land at the 318mm at £2,020 and that is a solid kit with nothing to apologise for.
On an R132 or hillclimb build, ring us on 0115 647 8650. Wheel clearance for R132 calipers is the conversation to have before committing to a kit, and Cameron can work through the options in about five minutes.