OS engines are crap in the .40 .46 series. Magnum, TT and ASP gives better bang for the buck and will out power the OS. The Magnum and ASP .52 2-strokes will out power the OS .50. The bigger OS's are better than most other engines I've seen.
Their 4 bangers are too heavy and when they decide to give you a problem.....watch out, very fustrating. I'd give YS and Saito my money all the way. The Magnum and ASP 4 bangers rock also. More power than the OS's.
The OS's are way way over rated and cost too much........give other engines a try as I did. You won't regret it.

Cheers.