Hi guys. I'm a little late to the party, as usual. All the same, I hope I can add some of my experience. We've tended to go through similar pains in the E24 world. Anyhow, on my B7 Turbo Coupe, one of the best things I've done for my front brakes was to upgrade my
rear brakes. The e24 (and 28) back brakes were notorious weaklings (in fact, I was shocked to see that Alpina also used them). Putting the e34 540/M5 rear brakes on my car totally changed it's braking character.
Prior to the change, the car would nosedive on hard braking. I never tracked it with the old brakes on, so I never experienced fade, but I'd bet it wouldn't last a 30 minute session as hard as the fronts were being used. After the upgrade, the braking balance became much better, and the car squats rather than dives - it's much more stable under braking (my pedal travel did increase, but only a small bit - I actually like it because it allows me to modulate the brakes easier). I've pushed them very hard at Sebring and never had a bit of fade. At the time I upgraded the rears, I also put on slotted rotors, front and back. I have been using Hawk HP+ pads - they are dusty and noisy, but they grip like hell. They're a little less grippy when cold, but I figure if you push a car hard enough when it's cold to need to make a panic stop, then you're gonna have bigger problems than your brakes, for sure.
Anyhow, what are the specs on the rear brakes on your B10's? Has anyone tried upgrading the rears to see if it relieves some of the pressure on the fronts? Now if I only had a BiTurbo to experiment on myself...