Uh... this goes against everything sacred, but I just scuffed mine up some, used plain ol' rattle can auto primer and followed that up with Krylon black from Lowe's.
At the time, I was scoffed at. And even I'll admit it was just sorta a low-budget, Cheapbastardish experiment. I was told it wouldn't last two months. That was back in, like, October last year? Maybe earlier?
But I'll be damned if they ain't holdin' up just fine. As are the exhaust shields, which got the same treatment. And no, it's not even high-temp paint. I used "gloss" black, but it has dulled a bit and is now looks about like the engine cases, a slightly glossier-than-matte finish. I don't wax it. Wash as normal, scrub bugs off, etc.