Get them chrome. Bare metal will rust really fast. Black powder coating is going to be a pain to keep clean. Ever have a black car? You get any kind of water on them and they will water spot and bake on there.
Chrome is a tough surface. When you get a little burnt on oil on the out side, around where it conects to the engine. Get some 000, or 0000 steelwool, soak it down with some acetone and scrub away. Try doing that to any powdercoated or ceramic coated pipe. The coating will come right off. If you dont chrome them now, it will cost a lot later if you run the pipes and decide to have them chrome plated, if you can find some body that will do used pipes. They have to be cleaned out so they are spotless other wise they will contaminate there solution tanks.
If price is the problem I wouldnt sugest getting them ceramic coated. My single exhaust header on my raptor cost $150 dollars to have jet hot coat it. It is a pretty safe bet that one side of the banshee takes more coaing than my raptors exhaust. It is hard enought keeping it clean from just water and a little dirt. I absolutly dont go mud bogging.