I just got back from a ride after putting this exhaust system on my '06 GSXR-1000. All I have to say is WOW! It was easy to install, the directions included were awesome, and clear ( I would recommend getting a factory service manual first. ) It sounds great. It's not annoyingly loud when you're just crusin', but has a nice tone at around 5,000 rpm and up. I also have the FactoryPro velocity stacks and a BMC air filter, the yoshi system just brought it all together.