I would suggest that you look at the KIPS return spring to make sure it isn't broke. The 06 is one of the meanest 250's Kawasaki ever built, don't know your abilities but I doubt that your riding it to its full potential. in the right situation with right rider it will walk a 450, they put out ove 50hp. most of the woods guys are going back to two strokes for the ease of riding. this generation of 250 has a pretty agressive port job already. I'd make sure everything is right and work on the too stiff suspension rather than try to get more HP out of it, oh and make sure your clutch is good so your getting all the power to the ground.