Jimax

I just did this on my 98 M3. Replace all the brake lines, rebuild the 4 calipers, put in a Motul 600 (DOT 4) fluid, and install the Hawk HPS pads and new rotors that you just bought.

Other fluids are absolutely compatible with the Audi brake system. Audi brakes aren't so special that they require their own fluid. I've run my car on the track for 16 track days, all with Motul 600 fluid. I've always heard that you need to cycle the ABS pump, but in truth, I never have. I've gotten air in my lines one time due to an improper bleeding procedure. That was my own fault.

The other thing you can do, is if you are going to use this car on the track, look for a set of B5 S4 HP-2 calipers/rotors/pads. The B5 S4 calipers are a direct bolt on to the B6. They are dual piston and also quick change calipers. I use these on my car and if I have to replace pads at the track, being able to do them in 3 minutes/side is priceless.

Audi OEM brakes aren't really pathetic, if everything is working correctly. Are they track-worthy? Of course not. But very few stock cars brakes are track-worthy. But in a regular street application, they do a decent job.

Brakes really aren't that hard. Pads are your biggest bang for the buck. Fluid, next. Lines after that. If you want to make a bit more of an investment, then get the HP-2 calipers, I guarantee you, you will be happy with your brakes then.

The Hawk HPS pads are a good pad as well.