For those looking to upgrade their brakes, has anyone looked into these:
http://x3.xbimmers.com/forums/showthread.php?t=1449394
Basically they're selling the adapter brackets to fit both the front and rear M5 brakes onto the F25/F26. I think this is similar to what Ultimot sells (referenced earlier in the thread), but I think Ultimot was a full kit, and this is just the adapter brackets.
There are some things I like about this idea:
1) For the front brakes it uses the M5 caliper vs. the M2/M3/M4 caliper. While the 6 piston caliper may be overkill, it does offer one advantage; how the caliper mounts. The 4 piston M2/M3/M4 caliper has the mounting bracket cast as part of the entire caliper. As noted earlier in the thread, the mounting points for that caliper do not match the F25/F26 hub. The 6 piston M5 brake calipers bolt into a bracket, which bolts to the hub. As such, you can modify the bracket between the hub and the caliper to fit the caliper perfectly.
2) This kit does include the rear brakes, which appear to work with the F25/F26 ebrake.
3) Outside of the caliper brackets the entire kit is based on OEM parts. From the perspective of OEM quality and availability of parts, this is nice. Additionally, it looks like the OEM rotors are the correct bore and will work.
The downsides (outside of overall cost) are as follows:
1) How does this kit mess with brake bias? Without getting into the principles of brake bias, my concern would be that bias is shifted forward which reduces overall braking performance. There are brake force calculators that can help with this exercise, but coming up with the precise measurements may be difficult.
2) Wheel fitment. Would these work the with the 19" wheels that came standard on the m-sports, or would an upgrade to 20" (or aftermarket) wheels be necessary.
What are everyone's thoughts? Anyone willing to try the kit?
***If you're going to respond to say that a brake upgrade isn't necessary; that is fair. However, I'd like to keep the discussion about this kit focused on people who want to perform the modification, even if you don't think it's worth the time or money. I think that view has been adequately represented here.