Nope, the sunroof does not hit the rack.
So far, biggest problem is that when the rack is unloaded, it whistles a bit at high speeds. I'm going to try and move the rack about 5 inches back and add a faring to stop the whistling.
I'll post again when I get around to doing that.
If anyone else is interested, I installed a Yakima faring, and moved the rack back on the roof about five inches. This totally stopped the whistling sound that the rack was making at high speeds. Hoped my Miles Per Gallon would increase substantially, too. It did help the MPG, but not by much.
Otherwise, the rack has been attached to the roof now for almost two years and haven't had any problems. Took a 3,000 mile trip in the winter with two Rocket Boxes and had not problems. Still really love the 2011 Traverse except for the gas mileage and the smallish rear window.