All four rotors warped after a few thousand miles

After a few thousand miles began experiencing vibrations when braking.

According to the dealer all four rotors needed replacement because they were warped (the rotors).

Not real confidence inspiring.

I went ahead and replaced the front rotors with drilled-slotted rotors. If those hold up for more than a few thousand miles, will probably upgrade the rear rotors also.

Brake rotors almost never warp: https://www.bimmerfest.com/forums/sh...3&postcount=17

Drilled rotors are, with modern pad composition, not much more than aesthetic improvements. The original idea behind it was to allow off-gassing from the brake pads to escape, back in the 60s. Modern brakes really don't off-gas that much. Slotted are roughly the same story: http://www.8thcivic.com/forums/suspension-brakes/92039-cross-drilled-rotor-myths-dissolved.html

I have personally found that if you tighten the lugs to correct spec. with a hand torque wrench, the rotors will not warp. If some jackleg uses an air impact gun with a torque stick, they will warp. No matter how good they claim the torque stick is, they can not guarantee that each lug nut receives the same NM.