I'm interested in upgrading my pulley but don't want to change the stock belt sizes. I saw one by (http://www.unorthodoxracing.com/uSSc.html) unorthodoxracing and they say that it uses the stock belt sizes.

Has anyone used this pulley and what are your opinions?

 

It Will Free Up Weight (rotating Mass). I Can't Remember What The Weight Difference Is But It Is Quite A Bit! IT Should Free Up A Few Ponies.

 

I have one. Slight but noticeable difference in revving. Nothing power-wise, though.