I can't comment on other pipes, but my 2000 Sxr6 (16,000km+) has benders!
It's faster after 50mph than my new 600 Cat & that's saying something
It's real important that you wrap 600 pipes or you'll suffer trying to maintain heat in them! Mine with cold pipes is no faster than a stock Sxr6 so you see how important that is!! You'll either have to get ceramic coated pipes or heat wrap them (which is tough with limited space under the hood).