its pretty loud, but they have a spark arrester/silencer kit that is supposed to bring it under 96 dbs. i have it for when i go places with noise regulations, i just havent been anywhere that i needed it yet so its sittin on a shelf for now. i have a few good spots but they dont have noise regs.
i am using the trinity stage IV full pipe with the efi controller and a high flow filter. i cant even tell you the difference in all around power and throttle response. i definitly recommend it if you decide to change pipes. they've also got a 734cc kit, so if my top end ever goes its time for an upgrade!! anyway you should check out the pipe setup. 13hp gains!!