Re: Scuffed Pipe... suggestions...?
Most aftermarket exhaust makers sell repair/replacement parts. Call/contact Erion and see if you can get a replacement sleeve and how much (perhaps you can get a different material if you have considered a different one in the past).
Then find out if they will do the replacement (how much) or find a local shop that is willing to do it. I would imagine you are looking at drilling out the rivets, disassemble / reassemble and re-rivet. Just like re-packing, and should be pretty simple and pretty cheap (if you do the labor yourself).