I live in California and so far they don't check bikes for smog but who knows when that will change and who knows if they will require a C.A.R.B. (California Air Resource Board) compliant exhaust. While a pipe won't change emissions a fuel map will. Arizona has bike smog but a few here have said that even with they pipe and map mods they passed that states testing.
That said, I have a Hawk Performance Muffler and I like it a lot. Drummer is nice too. I was able to hear one the other day and it was a bit deeper sounding than my Hawk but just by a bit. It is almost 3 times as much though so I went with the Hawk.