Well the 2 strokes have um, 2 strokes and the 4 strokes have, well 4 strokes I guess. Everybody should own at least one 4 stroke just for the experience of it. Propping them right can be a challenge. When i bought my Saito 100 a couple years ago, I tried propping it for speed without going over the rpms limit. Did okay but was not use to the 4 stroke sound. Really threw me off. Since you associate speed whit a scream, and here I am cooking right along but the engine sounds like there is something wrong when its fine.