not bad. here is a review someone did on the engine:
I've had this engine for about a month and it's treated me right, Follow the supplied instructions for engine run-in from RB and you won't go wrong. My friend help me tune this engine and kept the tempreture around the 230-250 degree range!! I ran about a gallon of fuel thru it all ready and I can keep up with the other racer's running Novarossi and Sirio Engines! Awesome Engine. Very easy to tune right out of the Box. Only one thing Don't lean this engine too much it will give you Big problems...
i forgot this engine. it's 150, but it's a very good engine for the new racer. you get full 8 ports, race design, and cheap price. a guy at my track runs it and it keeps up with an RB WS 7II, the meanest RB out there. check it out. plus, if you order soon, i think you can save $25 on it!