I have a Fastman standard bore 85mm ported TB. It is not ported on the back side. When I bought it all I had was intake and exhaust. After talking to Dan he advised not to get his performance TB as I didn't have enough mods to warrant the extra porting. Now I have BV Heads and Cam upgrade. Would it be worth the coin to upgrade to a true 90mm TB? I know I'd have to open up the intake to take advantage of this. May even go to a Vararam also.