Honestly I doubt that this engine is really any better than what you have now.

Are you looking for higher speed, better acceleration, longevity, ease of tuning, parts availability...?

Any .12 sized engine will fit as long as it has the same cranckshaft type (threaded or sg). If you want a great all around engine that will last, will be easy to tune, make you go faster and accelerate faster and be easy to get parts for AND is cheap you really can't go wrong with an OS 18cvr. You REALLY should go up on the gearing if you go that route though. That will give you VERY high speeds.

Enjoymentboy