I had them installed on our '05. They don't stick out much, just enough to keep stones off the paint. Most people wouldn't even notice them if I didn't point them out.
Mine came from GM and installed at Dasilva's a few years ago.
I bought mine a couple of years ago for the 08C6 and they really don't stick out much more than on the Z06, and cost about $100.00 for all four from GM.