I would wait.. The new units will be here in February.. personally, I think they look better than the one's out now.... even though I haven't seen them in person yet..
I just purchased my 9815 and less than a week later find out Alpine is coming out with new models. I thought about returning it and waiting but the '15 is so sweet! Went from the factory Delco CD unit to Alpine, a major jump. From what I've seen there isn't much difference except appearance, but if you wanna wait and pay a few bucks more for the new ones go ahead. You might find a good deal on the 2003 models that are still great units.
Really as everyone says the only thing that will change is the looks. Preformance wise they will be the same, just depends if you want to wait and if you like the new looks.
As far as anything besides cosmetic changes... not much has changed. MP3 is MP3, XM radio is XM radio. 4.5V out is 4.5V out, 100+ s/n ratio is 100+ s/n ratio. It still plays CD/CDR/CDRW, etc. What I'm saying is that there isn't much to "upgrade" this year or next except cosmetics.
What would be nice is a mobile SACD player. Now THAT would be an upgrade.