RE: Futaba 9C Radio
If you are flying on 50 and don't run into conflicts, then you dont' really need the synth module. The synth adds about 50% to your battery drain, so you will have shorter battery life with the synth module.
I would say skip it. YOu can always get it later.
The 9303 has a great reputation, but at a higher price. Only you can judge if it is worth the extra $$, and why.