You' need app 50W per pound of aircraft for decent performance, a little more for acro, less for a trainer. a 400W setup will outperform any standard .40 engine in a trainer. Hell, even father and son Matt are flying electric 2x2m pattern ships as YS 1.20 replacements in the world championships.

A 4S 5Ah lipo pack with one of the big AXI's in a 400W setup would weigh less than a .46 setup, have more power, turn a huge prop and run almost completely silent.

The downside is of course the price that would be almost $500 for the whole thing, but if you want the best, why not?

The quality and performance is available, its all about price.