Rotors are a fairly well understood subject at the track, the wavy washer behind the disc are replaced at the track on a regular basis, retainers removed and replaced with after market items. However fitment of rotors by some of us amateurs can cause problems. EBC will tell you that you should take great care to make sure the rotors are centered in the caliper, in one past situation I had to put a 20 thou spacer between the lug on the fork leg and the caliper, a pain but no more adverse wear or drag on pads and rotors. EBC were of the opinion that after I warped a set it was my poor fitment, I had to agree in hindsite, they blamed it on variable OEM tolerances that can cause this problem.
A by note, I just replaced the pads on my FJR art 32,000 miles and the inner pad was almost gone and the outer one looked good and healthy, the mechanic said this was normal, but it was disappointing.
Neville