Buy a new variator or just change rollers?

Right im thinking of buying a ´stage 6 sport pro variator´ for my zip sp as i´ve heard that it works well with the stage 6 pro replica exhaust. http://www.pedparts.co.uk/product/530/stage6-sport-pro-variator--piaggio
If i was to buy this variator would I have to adjust the roller weights or are they perfectly set up to work well with the stage 6 pro replica exhaust?
Or am i better off saving 40 pound odd and changing the roller weights in my current standard variator?
I have not fitted the exhaust yet btw its still got the standard one fitted