AI- I would definately go with this engine OStz .12 3 port...
http://www2.towerhobbies.com/cgi-bin...&I=LXJFY8&P=ML
It's a t towers, but it's at $250 USD I know it's a bit expensive at the time, but my R-40 buddies here in Guatemala already ordered 3, so I guess depending on the performance that could be my next engine...