I'm considering a full interior swap with a 92.x (door and side panels). I own a white 2002 WRX...
Anybody have advice.....? Will it be possible? Will it be ugly? Will it void my warranty?

Probably possible, no warranty on anything you swap, and as for ugly... well, look for pics of the Saab interior and judge for yourself. :p

I'm not worried about the warranty on those devices... i'm worried that if I swap the seats... will I then lose my warranty on the drive train!?

nope, unless your seats are connected to your drivetrain, last i checked mine werent :D

yeah.... that's what i figured... sometimes they can be crazy about those warranties though

You could get the STi's (05) interior. The door panels are the same as the 9-2X's, but in blue. The seats are the same as the 04 STi's. You shouldnt have any warranty issues with the swap.

Nick