I have an Akrapovic exhaust on my Super Ten. I agree with the comments already posted. Not much louder than stock, but with a little more growl. It is a very, very nice sound, and looks great as well. ::008::
Based on the comments above, quality and its an OEM optional fitment I've just bought one from Italy for a very good price saving over £150 on UK Yamaha dealer list price as I want something with a bit more sound than stock as I am tired of noisy silencers that I have had in the past on other bikes. Must be getting old!