when the new key fob comes out for the 05 would we be able to but it on the 03-04?

 

I assume you are talking about the Intelligent Key. Apart from the physical differences, it is a pretty complex system with a new Immoblizer chip that's fully integrated in to the engine control unit so I would have to say it's next to impossible to retrofit the 03-04 with it.

I think it's kinda of cool, and I am getting it on my '05 but I would still rather have the old mechanical system.

One bad thing about the Intelli Key is that if your battery is drained all the way or it's not connected, there is no way you can release the ignition lock even with the mechanical key inserted! It's a rare situation I'm sure but still, any electronic system like this should have a fully compatible mechanical backup IMO.