There this on my 2010 YZ250F and went with the stack to improve the top end. Install was super easy. I noticed a huge change to my bike's power during my first ride at the track after install and I couldn't be happier with how much improvement I saw. If there was a bike to put this product on, it is definitely a YZ250F. It greatly reduced the flat feeling that was there in the higher gears and the hit off closed throttle is awesome in any gear!
****HOWEVER****, once i got the boot installed and was wiping off the finger prints, the MT logo on the boot straight ripped off! The raised red pieces on the logo are glued on like garbage and nothing I tried would get it to stay on. Spending $300.00 dollars on what amounts to $10.00 of rubber and having this happen is a huge bummer. I've tried to call their customer service line on three occasions with no luck of actually getting anyone. For this reason, I gave the product 4 stars instead of 5. Putting aside this single shotty aspect of the air boot, I would say the product is a definite 5.