I have 2 YS 45 side exhaust, 1 rear exhaust and a old 120SC. Love these engines, I just wish I could afford the newer YS 4 strokes on the market today. The only problem I have with these engines is the high nitro for the 4 strokers, I run 20/20 in mine and 10 - 15 in my 2 strokes. The 4 strokers are more expensive to run then other engines. I'm the only one in our club who fly's YS. The others say they're a pain to tune, just a short learning curve that's all. I run them on the pipe and off the pipe muffled. Would be nice if they could come up with a gas version YS
