since you say the rotors were fine initially and then went bad, i'm going to say it comes down to cheap rotors. it sounds like after they heat-cycle a few times, they get warped. maybe bad steel??

how are you breaking in the new rotors?

 

I'm leaning toward the cheap rotor culprit. One confusing thing is a friend of mine put the same rotors on an R32 and drives harder than I do and had no problems (which is why I went with them in the first place).

I bed in the brakes just the way the instructions called for. Especially the second time! Specifically, 3-4 stops from 30-10 mph, then another 3-4 from 50 mph and a couple from about 65-70 mph, never coming to a complete stop, and then driving a few miles to allow the brakes to cool. I hope that was the proper way to bed them in? Also, I was very careful about torquing the lug nuts because I had heard they could effect braking related shimmy.

If I didn't have any symptoms of suspension problems before I changed the rotors and pads, could that still be a consideration?

Maybe have the tires rebalanced?

 

Having new rotor sent to me free of charge and I'll replace it in a couple of days. A friend of mine is going to help me measure the run out before I put it all back together and drive it. We'll see if this fixes the problem! I'll post results.

 

Received the new rotor and the problem is gone. Measured the run out on both the old and new rotor and found I had .008" run out on the old one and less than .001" on the new one. Thanks for all the suggestions.

 

Rotors become warpped when they get too hot. Obviously the thinner the rotor the hotter it gets. I'm not sure how many miles where on the new rotors before you resurfaced them, but they're probably defective. You could have a hung caliper too, either a piston or a slide pin. Most rotors can only be turned once, so there is no way I'd have them cut again. I'd have them warrented out. If the probably comes back its more than likely a caliper problem. FYI: 9/10 if you resureface the rotors of any German car they're going to squeak every time you brake.