The computer and the catalytic converters are different, I dont think much else is. And you can have your comptuer updated to the 04 program (prevents the stall).
ECM calibration is different (AMZ1?) and so is the mid-pipe design. Besides those two things the only other differences are the available exterior color choices.
Do you what's different with the mid-pipe? And about the stall... mine has done this a few times - it just dies. Only like 3 or 4 times over the past two years, I was never concerned about it.
I just called my dealer and they said the stall is a true story and that they will flash the computer for free to fix this. I guess I need to put the stock h-pipe back on???