I haven't had a chance to do my clutch work yet. I do notice a power loss after going to 30s, but not much. It pulls the 30s pretty well in stock form. I can even sling the rear end around a little when I have some mud. I haven't tried doing donuts with them, though. With the right clutch work, it should be able to rip it up with them. Also keep in mind, my tire and wheel combo weights about 54 lbs. each, with 1.75" tread. Some 30s are a lot lighter with less tread.