RE: Four stroke engines
I'm still waiting to get that Saito in the air, should be able to this weekend.
I have noticed from bench running that it puts out a lot of residue from the bottom vent. I thought something was wrong with the engine but was told this is normal for Saito. I'm not sure how I'm going to like all that crap on my plane when I fly. [:'(] I don't get much if anything at all out of the OS or Magnums I fly.
So maybe you should consider the clean-up as well in your selection process.
ME, I'm leaning away from the mess; but I still have to fly it before I make judgement.