perfect choice, imo, for a used car paint. at the top of the list of all the "cheap" 3rd lines of the majors. I've used my fair share of both, and their 3.8 Singlestage system is extremely good. durable also. I use the 3.8 to paint my booth with (not saying its that type of product only good for booth paint) but it was pretty bad this go around. 2 coats of gm white covered the walls just fine for a booth. There were areas on it that were pretty bad with overspray.
Definately would use the single stage for a solid color.