Hey Leroy: I tend to go to power. But if it means sacrificing weight? I'M SO CONFUSED Actually I am thinking of the RCS 1.4 on the Goldberg Super Chipmunk. I know it is a 60 size plane, but I am pretty sure it will bolt in, and I think I can move all the radio equipment back to compensate for the extra weight, unless the servos and such mount way back anyway. Since it is going to be an inverted installation I don't mind if some of the head sticks out the bottom. Not sure though, I need to do a lot more research, and I'm counting on some feedback from here as well. I'm pretty set on the 1.4, I've read nothing but good about them. But I must admit the ZDZ 40 looks pretty tasty as well, what, with all that's included, prop and drill jig, battery and charger, ignition, mount, and muffler. I think there is actually more bang for the buck here at $430. But would definitely have to give up on a 60 size plane. Although I did squeeze a Saito 91 into my Tiger 2, a 40 size plane. As for mufflers I would E-mail them to be sure, I won't swear to it but I don't think they come with a tuned pipe. Always glad to help if I can. Garry