I just picked up a California Car Cover. I got the "Noah" one. Fits perfect and snug on my 2001 Z28. Car is garaged, but there is always dust in there. Without the cover my car would get super dusty within three days. I got the cover and put it on. This moring was the first time I took the cover off, ever. I was surprised to find not a single spec of dust, ZERO scratches. I am a perfectionist, so I see the littlest of little scratches on my car. My garage has incandescent lighting in it, so I see every little imprefection on my car.
The Cali Car Cover is awesome. I guess they guarantee against scratching.