I've had several TT GP .15's. They are a real nice bushed sport engine. I had a little trouble with some about four years ago with them having a loose crank/case fit when new. The one I have now is excellent! Like jaka said...put an APC 8x5 on it, load it up with some 10% nitro fuel and an OS #8 glowplug and have a blast. Mine spins an APC 8x5 @ 14K with 10% and the #8 plug.