All 99-04 seats are interchangeable. The wiring is likely already there. Check out www.wjjeeps.com
for just about everything you'll need to know about your Jeep, that site is a very valuable resource.
Also, if the wiring isn't already in place for power seats, it's not difficult to run a power and ground for them, so you can definitely make this work.
2003 WJ in Jeep Green Metallic
, 4.0/242/4.10's. 4" Teraflex springs w/ RE monotube shocks and IRO short arms, cheap intake w/ amsoil filter, 2.5" hi flow cat and back exhaust, lots of lights and other misc crap.
Check out my build thread here: Life lessons and budget build