I got the engine in my MBX RTR. I was impressed at first. I really liked its power and all. But then again I never experienced .21 power before. It was way better then my Torq .12 engine tuning wise and reliability wise. It did seem to run a little hot though. Around 300 degrees. It burned up about 6 spark plugs in 1 gallon. I guess that's not to bad but it seems like every time I turn around it burns up a glow plug. It has plenty of power to power my 7 pound buggy. It gets it going to 45 mph. This would be a great engine for 1/10 scale custom projects. Imagine a 1.7hp engine for only $110 pull start in a 1/10 scale truck! It has 2 needles so its kinda easy to tune. If you have any problems just check this site out first to see if it helps, or email me or hook up with someone that knows gas r/c's well. For the price and reliability you cant beat it.