Just for grins, you might call a NAPA store to see how much rotors are. I was blown away when I had to replace some on a 01 C5. $48 each BRAND NEW OEM quality. Never had a single problem with them. I raced on them, did the twisty tracks - drags and street use, all without a single hitch. No shimmy, wobble, warping - nothing.
In fact,
Here you are:
NEW NAPA ROTORS FOR STS Just fill in the drop box, then go to bottom right screen on "rotors, drums and related parts"
Probably cheaper than getting OEM's turned.