Anyone get a chance to compare the sound quality in the 2003 Xterras vs the 2002? I'm assuming that SQ is the same, but just more juice on tap?

Yep. I've compared at a local dealer. My personal conclusion is that it's not worth the money if you think you will upgrade yourself later on.

Although, it seems the RF system does have more juice like you've mentioned. The rear speakers STILL stink the worst in the entire set, just like the '02 stock rear speakers. (All of the '02 speakers stink in my opinion, the rear ones being the worst of the set.)

Everyone has a different opinion and ear for sound. I think you should check it out to be sure. I've had friends say they liked the way my stock system sounded. I just hold a higher expectation for sound.

Where are the rear speakers? I thought the subwoofer replaced one of the original areas.