Mugen is not the only company that uses TIG welding.

Essentially if you buy a catback exhaust with 2.25" piping there's really not much of a performance difference between the available options out there. Anything with stainless pipes and a stainless muffler won't rust and will last a long ass time.

If you're going with a serious all-motor setup you'll need more than 2.25" pipes so the "bolt on" exhausts become pointless. If you're sticking to bolt ons you might as well get something cheaper unless you really really really want to drop twice the money as something else that will achieve basically the same result in terms of power increase.