Not very expensive at $300-$500??? Geez, what's expensive to you? [&:] But, I highly recommend the Mac .21, and even more so at the limited time offer of $209. Mine runs very well from top to bottom as well as another guy at my track who runs the modded version of the same motor. Idles very well and comes up on the pipe real quick. Great power and realiable to boot. Of course in your price range there are loads of great motors.