Congrats brotha!

About the engine you have to understand how a two stroke works. Basicly it is fuel in, air in, and in the correct proportions to create combustion. Altitude, temperature and fuel type affect this equation. The higher the altitude the less O2 in the air for given amount. The colder it is the more O2 there is in the air for given amount. I'm not into long explanations but it works the same as a snomobile engine. No magic here. Basicly no two stroke, non compensated, such as the Summit air box engine(snomobile) can be perfectly in tune out of the box. Now I have no experience with Evolution engines but they are all the same. Just want to let you know it's not an Evolution prob.