What is the best and cheapest way to improve a honda 400ex for handling and performance?

i have a 2002 honda 400ex that has hand guards and nerfs it is otherwise stock


any suggestions are appreciated.|||there is no cheap way to do it....





the 400EX has a very narrow power band for a 4 stroke.. %26amp; the max power is at the top of the rev range..





so to keep them moving at a great rate of knots you have to keep changing gear to keep the revs up near the red line..





you could possibly get a bit more out of it if you worked on the motor.. but the cost would be more than the benefit would be worth...