Yeh i know what ya mean there. Thing is if u want quality u gotta pay for it, there are really no shortcuts.
Hey if u can weld its not too hard to just weld straight piece of pipe through ure cat so it looks legit. Its gonna be a task finding a shop to do it for ya.
U just run ure zorst straight through and use the old cat casing to put around it and then weld the ends so it looks real.