RE: Radio upgrade?
It all depends.
An FM radio should give you better range and better glitch resistance.
They can also give you much more adjustability. If you're willing to learn how to use the features, things like end point adjustment, throttle deadband, exponential, etc, can help you get your radio dialed into your truck and how you drive.
Model memory is also nice if you have more than one vehicle to be controlled by one radio.
If you're willing to use its features, a new radio can be a nice addition.
Hitec crx, Airtronics MX-3 and Futaba 3PM were all really nice radios that i was considering. I got a JR XS3 for synth, and i'm very happy with it.