Just to give a wrapup on this thread: I got the G4 back, but it still has the same issues (since the hardware was replaced, I guess the G4 just has a major design flaw in its radio circuitry). So I've just switched to Centrafuse (with its own lesser set of issues) combined with a USB HD radio. I'm still out a few hundred $$ in installer fees, and a month without the G4, but I'd like to thank Goce from MP3Car for taking the time to try to fix the defect out of warranty.