Be aware that many (but not all!) warped rotor problems are caused by some tire changin' idiot who likes the sound of his impact wrench better with it cranked all the way up. A good 1/2" impact will put out well over 200 lb./ft. of torque!

I've seen wheel studs twisted off due to overtorquing.

My "rule" to them is that they can use that impact to remove them, but they will be torqued down by hand!! If they won't agree to that beforehand, I just walk away.

 

Just a thought, one thing that can happen to rotors that cause them to warp is overheating them (I am not saying you did that). When that happens, the 'high' spots on the rotors actually become harder than the rest of the rotor. This can cause the problem to reoccur fairly quickly. I hope the problem does not come back after having your rotors turned(resurfaced). But, if it does, I would recommend that they give you new rotors.