I painted some headers for my mustang with some high temp silver with ceramic, from autozone. The only place it flaked off was right at the head, where the temps are the hotest. I think I did not degrease the metal enough. Also they were stainless steel.
My only complaint when I used hi-temp silver spray paint was that the silver never stopped coming off whenever you rubbed on it. I'm told that's normal.
If so, I'd avoid the colors with the metal flakes in them (silver/gold, etc)