I put a Dynoport pipe and can on mine and never changed the clutching, it works fantastic just the way it is. Ride it for a while, you'll see. Then if you still want to change talk to Ken @ Specalty sleds.
The clutch updates from Ski doo still suck. I have reclutched my 07 xrs 4 times. Regeared 4 times as well. Vent kits done. Make sure that you clean your air box beofer you ride this season. Mine was totally full of belt dust and that was getting into the engine. I just changed by track to a regular camoplast not the lite junk.
what did you end up with? mine 44/40ramp purple/yellow spring[i think] 19/45 gears never burnt one belt last year 1100km woks great,awsome back shifting........