A k&n filter is a good and easy mod and makes a hell of an improvement
Also when ordering the filter order the proflow mount for it and take air box lid off.
you will have to re-jet I have a 2000 Shee with the same pipes and I am in the middle of doing a total rebuild.The Shee is bored 20 over , K&N, Iadded the alum water impeller, wisco piston and rings, Billet clutch, boost bottle(regulates the air between the carbs,, low end) NGK pluggs are the best I can run forever and only change to do it not cause I have to. Other than the motor I added fornt end +2,+1 in the front and +2 durablue adjustable in the rear..