Have u guys looked into the Novarossi N21b or the Top T21BF which is the exact same engine?? They tested it on the X dyno at 1.33hp and 59 in/oz of TQ!! Thats more then last years Novarossi 5 port P5X which is a 300$ mill which dynoed 1.11 hp and 44 in/oz TQ. The Novarossi is only 189$. I have one on my Mayhem buggy and its a beast. Takes a lil over a gallon for the engine to get broke in due to the VERY tight tolerances on the sleeve and piston. But once broke in its a screamer! Walks all over the OS RG with ease.