I've never had a Jap cat back, I thought the main reason was noise, since they're all certified to a certain (quiet) volume.
I'm extremely happy with mine as is, and for me it's right in the sweet spot volume wise. That said, if mine is too loud, you can just order it with a bigger muffler, problem solved?
Depending on who does it locally, either way you're going to get a quality result. I think it'll probably come down to volume, and if it goes to someone who hasn't got experience building exhausts for these things it'll probably be too loud. Mine was first time, but at least you can go back to the local person and get it fixed.