I don't know. One of my buddies that has a gsxr 600 just traded his two brothers for a stock pipe because it was too loud and high pitched. My other buddy still has his on (full exhaust) his FZ6 and I think it sounds like crap. It's way too loud, high pitched while riding, and it is not smooth sounding. When he's accelerating, it sounds like his bike is cackling, like a straight piped honda civic. Maybe they sound better on an FZ8 but the two that I have heard drove me away from it. I don't need a ticket. I bought a Danmoto carbon and I love it. I have a nice deep tone below 3000 rpms and it sounds like moto gp at 7000 and up. Plus it's not overly loud, it's cheap, *(and depending where you are) you won't get pulled over by cops. I know here in California, certain cities are really cracking down on noise for street bikes. I know a few people that have gotten tickets for their bikes. I have yet to get a cop to even look at me.
By the way, no offense to the people that have a two bothers exhaust. To each their own.