If you are talking about the steelies, remember they are steel and will need to be polished then sealed to prevent rust. If unpainted and just polished, it will rust FAST!
-Chroming may be complicated w/ the stock paint on the rest, see a chromer for that info.
-Another option would be silver paint (not polished) or a chrome snap-in lip.
If using the stock steelies, I'd HIGHLY advise painting them. The stock paint oxidizes and wears off quick. After 2 years, my bare rims began to spot-rust, as the paint oxidized, came off, or whatever and left random spots of exposed metal surface.
If talking about an alloy, it is MUCH easier, as the aluminum is easily polished and just has to be cleaned.