The OS 18 CV-R(X) is a well built engine that has pretty good power and very easy to tune. Definitely worth the money. I ran a 15 cv-r(x) for a few years in a xxx-nt 6 years ago and I got 12 gallons through that thing. Sold the truck to a guy that got a few more through it. I had the 18cvrx for a while as well, but basically just enough for break in. The break-in went pretty smooth and power was fairly strong, then I sold that truck too... sold the engine separate. Wish I had kept the engine now. At the time all I had were BB trucks.