I have a 2002 SSEI. The 2003 offers the OEM radio but factory ready for XM radio. I know I can get after market stuff, but is there anyway or hope I can get the 2003 radio that is XM ready so everything looks stock and matches??

You're more than likely gonna need a harness, not just the radio. The 2002 probably wasn't pre-wired for this option. The harness may not be much, possibly as little as a satellite capable antenna (hidden under the dash, most likely....at the wavelengths they transmit on, it will be a very short antenna). The other connectors on the radio are PROBABLY the same. You need connections at a dealer so you can pull the stereo from an 03 and take a look.

So you think the radio may be the exact same radio just a different harness and inputs to accomidate the XM radio signal??

Possibly. It may be the reciever antenna is actually built in to the radio itself. If that'* the case, your odds are better. The dealer is really the only place to get this answered.