If I bought anything from any of those companies, it might be CT. CT and White Bros consistently win pipe/silencer HP shootouts. Other than that you're just wasting your money. The reason WB and others had such a time "improving" the stock head-pipe, was because they couldn't. That's the reason Polaris dropped the add-on head-pipe. Spend your money where it counts, gear that will improve performance, handling, quality of ride. Don't spend it on hype, cause that's all some of these people are selling. If you let them set the hook once, they'll do it over and over till your cash is gone....and then I'll just wave as I pass.