For 3d work I would go for a 120ax, ys110 or saito 125-150, but OS runs happy with lower nitro, ys is pure power and let you put the tank in the CG but drinks a lot of 20-30% nitro, and Saito is easier to tune using 15-20%nitro .... eeeem I know I`m not claryfing anything but if you like to go gas then go for a 50cc plane for good 3d performance