I have an os .25 for my truggy and couldn't be happier. As with all os motors they're easy as to tune and will keep running for you all day without a flame out. It has alot better bottom end than a .21 but not as much as the fire breathing .28 where you used to change clutch shoes with every tank and the diffs with every glow plug.

Best of both worlds and superb bang for buck value.