I just bought my 2007 RXT a few months ago...
I had the supercharger rebuilt and took the ski out .
I was only hitting about 7300 rpm at full throttle... I bought Candoo and found out my throttle cable had stretched and the throttle wasn't opening all the way.
I adjusted the throttle cable and now I'm hitting 8180 at WOT..
and get those ceramic washers out of that supercharger ASAP!