I had just sold off my 300 kit and got another bone stock cylinder. I decided to send this one out to get ported. Stock Yz250's are very smooth and easy to ride. This is a little bit different now. The bottom end is soft and mellow, fast but soft. Once I am past 1/4 throttle it explodes. This motor is an absolute rocket ship. It revs so high, I can hold the gears out another 2-3 seconds over stock. It will run with a 450 at the gate and out of a corner, the motor is a gem and an absolute racing masterpiece now. Aggressive, but very tractable oddly enough. Service was great, Derek is a good dude. 10/10 would recommend this product and his work. The setup is the stage 1 porting, stage 2 piston, timing advance 3 degrees, head mods.