Brembo 300ZX Brake System [4-Piston 13.125" Rotors]

So i need some help from some with mechanical skills, a while back i got a new set of wheels that i put on without a torque wrench -- and i got them too tight -- anyway i got a torque wrench and redid the job but it appears i was too late -- i think i have warped my brembo rotors -- symptom - steering wheel chatter and low speeds & light brake pressure - seems fine with a heavy pressure on brake:

Is my diagnosis correct ?
Can drilled rotors be turned?

thanks

seems right. you checked lug tq's first?

most places do not like to turn drilled from my exp. are you holes just straight cut? or chamfered? (sp?) i think if you have that taper it would reduce the chance of cracking.. but it all depends on the shop. thats a big liability.