Here is what I saw:
325i and 330i - Coupe and Convertible (Available since March, 2003)
* Automatic headlight control standard (formerly optional with Premium Package)
* Revised front-end design
* Revised front and rear bumper contours
* Xenon headlights (low and high beams) now offered in combination with new Adaptive feature, which "steers" the headlights into roadway curves
* Revised taillight technology, incorporating BMW's innovative Adaptive Brakelights
* Revised wheel designs, both standard and optional
* Revised exterior colors
* Revised configuration climate-control panel
* 6-Speed SMG (Sequential Manual Gearbox) Transmission will be available on most rear-wheel-drive 3 Series, when combined with the Sport Package as of 10/03 production. It will not be available with all-wheel-drive or the 330i Performance Package.
* Rain-sensing windshield wipers and automatic headlight control will become standard features on the Sedan and Sports Wagon - no longer part of the Premium Package (already standard on Coupes and Convertibles).
* Sirius Satellite Radio is available as an accessory.
Okay - Even though I was one of the first to take delivery, I still had all of the options above. Front end & rear end are redesigned, xenons & lights, wheels on the 325 are all new as with the optional run flats on the 330. The new colors are available, however I don't see a difference between the '03 & '04 climate control panel. The only thing that wasn't available to me was the SMG. 6 speed was standard as were the rain sensing windshiels wipers & auto headlight control. Now with the adaptive lights, the only time you really notice them is when you quickly turn the wheel (as if trying to avoid something in the street). Thats when you really see them move. At slower speeds the lights actually contain themselves and broaden their width so you have a better view of the side of the road. And at higher speeds they elongate their light so you have maximum distance visibility. Now I do not believe that you can get regular xenons on the 2004. It is either the standard halogens or the adaptive xenons. Now the adaptive part is cool, however I must admit I don't realize that I have them 1/2 of the time. Now for me, it was worth the $800 for the xenons, because I live in a dark area and wanted the brighter lights, but it comes down if you want xenons or not. If i had to do it again, i would definetly go xenon!
Now as for the sport package wheels, the link you provided said they were changing wheels on the **325i and 330i - Coupe and Convertible (Available since March, 2003)**. They changed the 325s but not the sport wheels on the 330. They did however switch the tires from Dunlops to Michelin which make a huge difference.
And as the link says, these changes have been available since March (when they started producing the '04s) so who knows if they will make anymore changes.
my $.02