I just got a new 06 CRF250R im looking for a couple good upgrades to enhance my my low end torque and power. Mainly riding in trails and a few Hare Scrambles.
I would suggest installing a hotcam stage 1 for low-end. If you want an exhaust I would try mrd-racing.com. They custom make the pipe to suite you and your current mods, and can get the screens for lower sound