On the losi belt, whe you cut every other tooth off, it actually makes your car faster. I isn't one of those, efficiency mods, or, it's easier to set up mods, it makes you faster. I'm not a pro, and i can feel it. Basically, when you off the throttle, you roll soo free, you can get so much more corner speed. Actually, i'm underrating this, it's better than i previously said. Doesn't wreck your belt, as long as you cut it right, and it's easy to install. When you rebuild you diff, put the new belt in. i did it on the blue belt, i can't imagine what it would be like on the yellow belt.