The very best with your search. Don't worry too much about the sound system and certainly don't let it be a deal breaker, as most of them part out theirs.
When I get mine done shortly we will see what gains mine has. Currently having my Motodyne Thermal Plenum Spacer fitted by Mopedmark. Having previously done the K&N Typhon induction and full customs stainless exhausts with Decats fitted.
That's really strange buddy, you would have surely thought by cutting a section out and re plating in would have lasted the time. Do you think they did the prep work correct before finishing ?