bare
Dude definately get the MM ones. They are the best. And get the bare metal ones. You have to grind down the powdercoating to get a good weld anyway and then you will want some kind of rust prevention on and around the welds so you will want to paint/seal them anyway. Bare metal ones mean less grinding, save the $ and get some good rust prevention primer/sealer and then some good paint and you are set.