Right On, they're a great engine! I'm certain OS went to the Surpass design due to machining costs. If they had revised the original design I'm sure it would exceed the Surpass in power.

The baffle screws out of the end of the muffler and if you can find someone to make up a straight pipe to replace it you will gain a good 300-400 RPM, then you will be par with Surpass. The thread pitch is from what I recall M11 x .75

Happy Fly'n....