Difference between 2003 and 2005

[Testtube]

What are the major differences between a 2003 hummer and a 2005 Iam thinking of purchasing a hummer and I am wondering if its worth it buying new. Granted i get a suppliers discount for new veh
But iam not sure if i can get it equipped the way i want it. So was there any type of "upgrades" done in the 05 model year that wasnt in the 03 Any info on this is greatly appreciated.

-Ryan