Early 04/2003 elantra?

[Codenomics]

Ok, so i have a 2004
BUT i had to buy a O2 sensor from a 03 motor.....
If i look up a 2004 Elantra in Kelly Blue Book my VIN doesnt match
I have been confused pretty badly here. I have been told that I have an Early 04, 2003 model.
So i have a 2004 that has some parts from a 2003.
Can anyone break this down a lil bit for me? What happened? Is this a bad thing? Good thing? no big deal?

[slyderdai]

I have an 03 with 04 parts(XD2 stamped) No big deal I guess.

[smileymattj]

wonder if someone changes code's car to the 04 stylings just to piss the potential owner off.

Now I could understand some mid year changes in cars, and left over inventory getting put into newer models (Chevy does it every time the trucks change styles). But newer parts in an older car just don't make sense. Not saying they ain't there, just saying if both of your cars are like that, that don't make no sense at all unless they came from different plants and different plans where being implemented at each plant.

[Codenomics]

mine is newer with SOME older parts.
It has an 04+ exhaust manifold, but uses the older 02 sensor
older o2 = 4 wire
newer o2 = 5 wire

And i have been told that they changed this midway through 04 and that there are more parts like this.

oh yeah and Kragen said something about it was because it was in california

[2003GT]

I have an 03 with the SULEV engine in it. I think my parts are stamped XD though. BOB