Hey Guys,
You could lighten things up by using the newer LiPo battery packs, they weigh about 1/2 as much as Nicds and Nimh, and offer about 3 times the capacity.
I am working on hanging my DA100 on my 330L, and as Don from Don's Hobby Shop had informed me, the BME102 will fit inside the cowl without cutting spark plug holes, as it is much more narrow. The BME is an awesome engine to boot. I went with the DA for it's torque curve, and the heavier weight over the BME to offset 4 digital alum case Futaba servos in the tail. (Although still lighter than the Zenoah's, the DA will help balance without adding weight, the BME will probably require you to use a heavy spinner, prop , batteries up front (but not too close to the ignition) and probably need some lead (unless you want a aft CG)