I don't see why you couldn't swap out the front bumper and grille relatively easy... and of course the rims. But the rear-end, that would be an extensive job, as the rear quarter panels are different. Afterwards, the trunk lid and rear bumper would have to be swapped out, and the taillights/reverse lights re-wired. I personally wouldn't tamper with a brand new car like that, unless, as someone stated above, the car were to get into an accident.

Everything in the interior can be swapped over to the 03-05, such as the new guage cluster (even though personally, I like the 03-05 guage cluster better)