I bought it. Put an extension on. Had to drill out one the holes to get the bolt in (too narrow by a little). Got her on today and took her up. I don't have a tach but no where near the additional power the Ultrathrust makes. I guess I learned a $30 lesson. I was willing to take the risk. It took a full turn to get it leaned out (to the right) and even then it was still a little rich. I'll fly it again in the morning and see what I think (I only get 15 min of flight a day). The verticle seemed great. I didn't run out of it. On the ground it wasn't fighting to get out of my hand like the Ultathrust did. We'll see. At the very least I have an extra muffler that looks cool as hell.