A Saito 150 won't be even close to enough for the DP Extr. A friend hhas one w/ an OS160 2-stroke and it's ok for sport flying. For 3D you need a glow engine of at least 1.80 ci or a 45 - 50cc light weight gasser.

FYI a Saito 150 will only 3D a plane weigh a max of 10 lbs.