Well, with a sunroof keep in mind that you get what you pay for. Go with the best quality that you can afford, and go with the best installer you can find. If you can get references from other customers, great. Not all sunroofs are created equal, so go with a name brand, such as Webasto, something with a lifetime warranty that includes leaking. I used to work in the aftermarket installation industry, and I can tell you stories that will make your hair curl. I wouldn't trust some of these gorillas to install a nail in a piece of wood without screwing it up, but there are some really good professionals out there. Don't ever go with the cheapest guys. Shop around. Visit their premises if you can.
Stainless rocker covers are decorative, but don't really do much other than look sharp. Once again, make sure that the installation is done properly, with rustproofing applied to the holes that are drilled. Done right, they should be no problem.