The Dupli-color vinyl stuff works pretty good too. I sprayed some old shock bushings with both that and the Krylon and did some tests. Hammer, clamped in the vice every which way, hammer while in the vice, scrape on the driveway...and was really impressed with both. The only thing that got through the paint was the scraping on the driveway and that's only because it was actually taking material off the bushing. Even then I had to rub pretty hard. The hammer and vice just made skuff marks, but the paint stayed put. I was hitting them hard and even hit 'em with the claw side a few times hard enough to put perminant dents in the bushings. Paint stayed put great. I didn't try any solvents though. Cleaned them with Super Clean and a brush first, hosed off and let dry, then painted. I did clean one of them, I think the one I painted with duplicolor, with superclean and it held up fine to that. I also did my washer reservoir and Pass. side fresh air intake with Krylon fusion several years ago and they are still nice and glossy with no flaking or chipping.
Not flares, but I wouldn't hesitate to paint any plastic with either.
