I had replaced the front rotors/pads on my 97 850 and after about 1 month the car was acting like the rotors were warped on the front- lots of vibration under braking. I inspected the brakes to find the rotors were not warped and still looked new, I then noticed the Engine stabilizer bushing on the top back of engine (connects engine to firewall) was completely worn and missing all of the inner rubber. I replaced the bushing with a polyeurathane bushing (NOT IPD they want 28.00 plus shipping, i can get it local for 20.55 includeing tax, email me for info, this would be less than IPD's list price including shipping to your address)After replaement I test drove the car and the front end vibration under braking was completely gone. Check your bushing next time you think your front rotors warped it may be the problem.