drv2e30

It would definitely be interesting to see if there was a bigger master cylinder. I believe the STI master cylinder is a bit of an increase, so it might be something to consider installing. Remember you did increase the size of the bore for your brake pistons without also increasing the size of the Master Cylinder bore. Both must remain within a certain ratio or pedal feel will change, barring the age of failing rubber gaskets or brake fluid.

I have an older E30 BMW that I completely redid the brake system on. The number one thing I did was get a larger master cylinder from an older 7 series. Though since you replaced your brake system completely I would replace the master cylinder. The seals in it are definitely worn out. -Sean