I have a different understanding of why the pipes rust. I have always understood that the extremely high heat trapped in the pipe causes the chemical make up of the pipe to change and become brital and eventually just go away. The thickness of the pipe is a big issue as well as the temperature of the exhaust. The cermic coating is a big help towards making a wrapped header last longer. If you wrap the sidepipes, they will show very little damage over time. The headers will damage sooner do to the heat. It is the same chemical make-up for siver or black. Black will accept paint better than silver due to the satin finish. You could have your pipes coated in black and use a high heat white to capture the look you are going for.
By the way, I really like the look of white pipes. They will require some touch up from time to time. Check my gallery for some pictures.
