SRX123 -
To really wake that sled up use one of Turk's cluctch/gear setups from the tech page that will best fit your riding style. The head gasket/airbox/silencer mods do pick up about 5-7 HP. The other things that really help to free up HP and speed are:
1. Have your jack and drive shafts trued - you would be surprise how bent they are stock
2. replace/repack all driving line bearings including the idler wheels if the sled has more than 3,500 miles on it.
3. Turn the drivers (while still mounted on the drive shaft) round and true along with turning the track tensioner idler wheels true (freeze them and them turn them)
4. Follow all the instructions from Betheviper for how to take the slop out of your suspension and align it.
5. When putting the sled back together get the jack shaft / drive shaft and rear suspesion lined up as close to square as you can.
6. do the reed cage mod
If the If you decide to do the silencer mod wait. I have one already modded that you can try and if you don't like it then send it back. if you like it, the price will be pretty cheap like $25+shipping.
Mills