You don't say what type of trainer you have, if you have learnt to fly with a tric under cart, it would be good to change one thing at a time, flying a low wing is a lot diffrent to a high wing, so stay with a tric, get some stick time on the low wing, then go to a taildragger . As for motors, I think it is good to spend your money once. The FX has a lot of power and wiith power any 40-46 model if you fitted the LA soon you will be looking for more power and will have to outlay more cash. and for a planes Vmar make a jodel it has flaps and flys very well and later on if you up the control movments it great fun. The only other thing I would like to add is that if you aren't in a club is safer and cheaper to have a good instructior beside you when things go wrong.
By for now Ozi