As chevync20 said do you have it jetted right? I have the eco, with a uni filter, 130 dj main jet clip on last notch of the needle with a washer under the clip, 2.5 - 3 turns out on the fuel screw, snorkle, and 27" tires. I felt a noticable increase in power, and I see a noticable increase, my buddy has a stock 450 and we race alot, I will give him about a bike length head start and I will walk right by him. When I was stock we would be about even from a dead stop, now I am definately faster. So You must not have the jetting right or something.