Ahh well first check out the sticky thread one thread at the top of the superjet forum. (right now its the thread above yours)
Here is my personal advice:
The things I would buy in order are strait bars, prop, and pipe.
Strait bars get you in a forward stance yet still comfortable and you can really get over them when you want.
The right prop will be night and day from a stock prop. I would talk to some shops about options. I got a prop and a bored exit nozzle from jetworks and now my 650 engine has more punch than a stock 701 superjet.
The pipe will give you a noticeable power bump, but get a prop first because the power gain can't be used to the max as it would with a prop. Once you get a pipe rejet the carb(s) properly.
Hope that helps. Ride hard