powdrecoating is not expensive if you remove the parts and clean them before you give it to the shop. lots of reputable spots as well.

 

I used flat black rustoleum spray paint on my brothers SC300. When we did the valve covers @ 210, 000. Its been almost 1 1/2 years and @ 232000 they're still in excellent shape. No peeling or anything yet

 

BBQ paint works best but for the valve covers you can nearly get away with anything. I disagree with the textured paint comment, as I've had success with hammered and wrinkle coat. The trick is preparation. Can. It stress prep enough. The parts need to be sanded with 600g to get them rough, a polished face will fail. Once sanded right use the paint as described on the label (or google painting tricks and find your own methods). Once you have the 3 or 4 coats on (remember spray paint is much thicker than air paint) you will want to use a matte clear coat "high heat". Baking is required on these parts because the first time you run the car hot, it will melt, if you cook them in the drying process it hardens it better. Now the most important part is dry time, some manufacturers recommend 24-48 hours, but I've learned that for auto parts it needs to be tripled, say a week or ten days.

In conclusion, if you powder coat them you have more color and texture options. Also it will be stronger and last forever.. Good luck.