Fatam,
If the car and the radio isnt working out, perhaps try another for yourelf next time at the track and then make your decision as to what feels best, drive your friends cars/radios at the track, then drive them some more. You wont know what feel's right until you experiment and talk to the locals. It's a good idea to run what a few choice others are running simply to share a parts/setup base with someone at the track, someone more knowledgable than you that you can feed from. Good Luck in getting all this squared away, I hope you get back to having fun soon!
peace and cheers!
TW