SW20 MR2 to Boxster (Non-S) Caliper Adapter REAR KIT (PRE-ORDER)

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  • Regular price $295.60

This is a Pre-order, it will take 4-6 weeks after purchase is placed.


This kit includes the following items:

  • 2x Rear Caliper Brackets (Made from high strength 2024-T4, Hardcoat Anodized)
  • 1 rear set of brake lines (2 lines, clips, brackets, crush washers, etc) 
  • 1 hardware kit (all bolts, nuts needed for install) 

Upgrade to a full set of lines with selectable options on the drop down menu.

What do you need to provide?

The items below are not included and must be sourced by you

  • 2x Calipers/pads (Porsche Boxster 1997-2009 non-s/2.7L, Cayman 2007-2008 2.7L) Rear
  • 2x Rotors (Toyota RAV4 1996-2003 front rotor 302mm) (yes RAV 4 Fronts go on the rear of the MR2!)


 The OEM part numbers for the calipers are as follows:

Rear Left 98635242301
Rear Right 98635242401


Frequently Asked Questions:

So what is the deal with this kit?  

A lot of folks are looking for something a bit nicer than factory brakes for the occasional spirited driving and track use and that is exactly what this does.   It allows you to adapt the 4 piston Porsche Boxster Non-S Calipers (which junked Boxsters are everywhere) to some cheap OEM rotors (RX8 and Rav 4).  You can use cheap pads for daily driving or purchase some really expensive pads for track use.  It is up to you.

Why these calipers and why those rotors?

Like the MR2, the Boxster is a mid engine platform.  Therefore the caliper/rotor combination are going to be close to the correct brake bias for the MR2.  After a lot of searching and calculations,  The Porsche Boxster Brembo (non-s) piston sizes and the pairing of the 303mm/302mm rotors works very well for maintaining the factory bias.  Works with both the NA and Turbo proportional valves, however I did adapt a Wilwood proportional valve to add the adjustability for track use.   In the end, We did some math, figured out this combination works pretty darn well with the MR2 without blowing the budget.

Do I need a master cylinder upgrade?

I have this setup on my factory 1994 NA master cylinder.  It has been working fine for daily driving and track use.  The upgrade to a larger master cylinder can be done, but we have not tested it personally.

Should I buy this over the Wilwood kits?

I am a terrible sales man.  The Wilwood kits (such as Wilhelm's) is a great kit and more geared to track use.  It comes at a premium but its a premium product.  This kit is more budget friendly and can be completed on a budget.  It works on street and track and is an upgrade over OEM brakes.  If money isn't an object and you want to do tons of track time, you may want to consider Wilhelm's kit.  If you are on a budget or don't want to spend the premium pricing for a Wilwood kit, this is a great choice.

What about the handbrake?

Sorry, this kit does not include hand brake components at this time.  You will need to leave it in gear or adapt a hydraulic parking brake.  I plan on adding a handbrake adapter of some sort in the future, but for now this will not have it.  The Wilwood parking brakes can be adapted to this setup, but no official mounting provisions or cables have been produced at this time.

What size wheels do these fit?

These have been tested with 16" R32 wheels and fit with room around it.  Therefore, the minimum official size is 16" as long as the wheel inner barrel does not have protrusions or other features that are in the way.  Offset/face design is still up to you to measure and figure out.

R32 16 wheel MR2 and Boxster Calipers

Unofficially, the rear calipers have been tested on a 15" drag wheel and appears it can fit but the offset was incorrect to get any real data.  Use a 15" wheel at your own risk!


Installation Instructions can be found here.