Jun 30, 2016 IMO the power vision is the best tunable tuner their is. most tuners will agree. IMO woods are 1 of the best if not the best cams also but size still depends on the rider so many people I know went 555 and love it to death just really depends how you ride. my new SS motor came with SS 640s. I am not sure how I like it yet as you have to be on it at all times. its just a monster that wants out of its cage. I dont always ride like that.