I put a 11oz in my 01, it is great imo. It allows me to ride a gear up and chug over more technical stuff. It did soften the hit a bit, but it is still is more snappy than my new 300xc. The xc is real strong and feels very unstoppable. It is rare that it stalls. The kx is fast as hell with the weight. I drag raced a 06 rm 250 on a fire road, it was close but green just pulls. He (the owner of the rm) rode my bike and said that his hit harder but my bike pulled and pulled. He thought it was much stronger off the bottom. I would recommend them for a woods bike.