I just used that Plasticote Gloss black. Work well, has a good finish and stays on well despite the heat. I don't bother with the fins. I don't like them polished and prefer to paint them too.
You can use heated paint that you get in the DIY for barbeques too. Good finish and lasts for ever, so be careful. If you plan on spraying pipes to black, or get some overspray on your shiney pipes, make sure you deal with it instantly. Once that shit goes on for a few hours, there is no getting it off....not even with paint stripper. Trust me, it clings that good.