Well.....

A: GWS is ok fer airplanes, but fer cars, it's suicide!
B&C:All you really need to do is toss out those GWS servos and get some Airtronics or Hitec servos, but if the problem still persists, then yer reciever is toast. In that case, just get a new reciever. If you really want a new radio however, the radios to get are the Airtronics M8 FM or JR R1 PCM. The M8 is an excelent radio because of its reliability and all of the digital bells and whistles. The R1 has all of the same great features that the M8 has, but the R1 has a PCM modual. A PCM system basicly eliminates "same channel" interference because PCM over powers FM and AM modulation. So, in english, if someone on the same channel as you has an FM system and you have a PCM system, you will over-ride his radio and you will have control of both trucks rather than both of you going out of control.