[PrematureApex]

Originally Posted by hardparker

Thanks. I'm fairly certain the braking was heavily rear biased before, since the pads wore out at the rear in just over 20,000 miles. It feels more front biased now, I'd say. There's certainly more fluid volume up front in those four piston calipers

The rears wearing faster than the fronts is very common in these cars with the "e-diff" constantly working the brakes. Completely reverses the typical -fronts where 2x as quickly as the rear-. Certainly don't look to pad wear as any indication of front or rear bias. If anything, a stock setup is going to be relatively more front biased vs. a more aggressive setup. Case in point, many front Brembo BBKs actually provide LESS clamping force than OEM calipers in order to shift some bias rearward, improving overall braking performance, reducing dive, etc.

Fluid volume has nothing to do with anything (sans some heat capacity on the track), you needed to look at total piston area. Again, plenty of 4 or 6 piston calipers actually provide less stopping power than factory sliders, by design. As far as stopping power goes, piston count is also not relevant.

As mentioned above, if you shifted bias forward (as you think you did), you actual HURT your stopping distances. Generally, the OE setup is overly front-biased for stability, despite the fact that the rear tires have a bit more traction left to give, particularly in the dry. If you gave it MORE front, while it might feel like you're stopping faster, you're giving up even more available rear traction, and actually hurt your maximum braking performance.

Point is, while I'm sure they're fine...there's a fair amount to consider (and to understand) before simply swapping rotors and calipers from another car onto one axle, and expecting improved performance.

Regarding the red stuff vs. yellow stuff, the yellowstuff's minimum working temp is a whole 100 degrees higher than the reds. Nominal friction coefficients aside (which applies to their rated working range), it's pretty well-documented about the yellowstuff's lack of cold temp bite (again, that may not apply to you). I do see they upgraded the compound somewhat recently, so maybe my experience with them in winter almost 10 years ago is dated. But Yellowstuff on a 15 degree morning backing down a driveway has been an eye-opener for quite a few of us. Not a huge deal once you adjust for them...but yeah...certainly lacking cold bite particularly compared to OEM pads, which are famous for their initial grab. Even a cursory google search reveals plenty of reviews stating the same.