SPEND THE EXTRA MONEY!!!!!!!

The OS 40 LA does not have bearings. The Evo does.

The OS 40 LA does not have much power. The Evo does.

The OS 40 LA does not come with a glow plug (You will have to spend about $10 more for one) The Evo comes with one.

Click on the "Magazine" tab at the top of this page, I just did a review of the Evolution Engine, and given a choice between it, or any of the OS LA series, I would buy an Evolution every time. (And I really LIKE OS Engines, but the Evo is a MUCH better deal than the LA series.)