I took a Magnum 46 out of my Extra and replaced it with a Saito 56 and had to add weight to the nose, that surprised me. My Extra now is a fun plane to fly. I agree with Minn I won't buy another 2 stroke because I love sound of 4 stroke. I bought an OS160 twin for my Stinson, I can't wait to hear that. Another thing I like about my Saito 4 strokes is if I just want to putput around I run 15% when I want to rip I run 30%, yeeehaaa