I would not get an aftermarket sunroof if any modification needed to be done to the car to make it fit. I would opt to pay for the factory Premium Power Sunroof and have that installed. I got a quote from my local Chevy Dealership in Phoenix (moving next week) and it would be $1200 for everything, installed, and out the door. He said that the ones that he has done lately have not come back for any leaks or problems and that they are under warranty after installation.
It comes with everything needed for the complete swap including the controls, New Headliner, Glass, visor/cover, wiring etc.
Something to think about. I know I am sure considering it.