RE: TURBINE CHOICE
I just went through the same scenario and ended up buying a Merlin 90K for my FEJ 1/8 F-16. So far I'm impressed with it but I've done only a few starts and haven't had a chance to fly it yet. Of the available choices I felt that the Kingtech and P-80 are too big and heavy for their thrust levels.
The Merlin 90, Rabbit, EvoJet Booster 90, and Wren SuperSport are all state of the art engines with excellent efficiency, power/weight ratio, and throttle response. The Merlin and EvoJet have the added advantage of kero start.
The best advise is to talk to the other jet jocks in your club. There's an advantage to flying the same brand as your buddies in case you have questions regarding set-up or parameter adjustments. It's a learning experience and the local expertise will come in handy.
Joe