I have a .52. I HAD it in a plane under a cowl and I couldn't describe to you what it used to do. Every day was different. Screw low idle in, then out, then no transition, then wouldn't start, then something else. I hated it. I bought a CG extreme 330 profile, and thought I'd try the .52 on that. WOW, what a difference. Runs perfect, plenty of power, unlimited verticle. The muffler fell apart, but I got a pitts for it and it's back in business. So it was either sitting in the wrong direction on the other plane, cause I have a new engine in it and it runs great, or it was the cowl.

I do have a friend who has a .46 and it sucks. I don't like to pass judgement on engines when I don't know how they were broken in or treated up until the point that I see them, because I don't know. I'm just saying this one was either treated badly, or was crap from the beginning. Horrible transition.

Seen a few Magnum 4 strokes that run great.