The most important thing is the project your trying to develop. the sound produced by a 2 stroke is more appropriate for a warbird type plane while the 4 stroke fits wwI or slower civilian type planes. I love the sound of 4 strokes but not on a quickie or formula 1 style of plane. the next thing to consider is that 4 strokes run better standing up while two strokes can be on their side or up-side-down. whatever you decide good luck.