I just received a complete stock system off e-bay (needed the header and mid pipes for Corbin beetle bags). Supposably it was off a 2006 that had an aftermarket installed before it left the dealership). The canisters and header look new, but the midpipes have dirt and a lot of rust stains deep into the welds, is this common? Won't you see the rusty (ugly) welds when the system is installed?