whats the differance between these engines that they make some stuff for one and not the other sounds like a dumb question but i dont know, and was wondering if i can put the 03-04.5 parts on my 05.

 

The exhaust is a different size. The 04.5 and later have a cat and the third injection event. I think the turbos are slightly different. I'm not sure what else.

 

03-04 Turbo's have a manual waste gate 04.5 on has electronic waste gate.
03-04 Exhaust is 3 1/2 inch instead of 4 inch I'm not sure when the cat's were put on.

 

And the numbers, 04.5 and up are 600/325 wile the older are at least 555/305. The newer ahve catalitic converters, older do not. Newer 4" front to back exaust, older have a 3.5 downpipe then 4" back. Better fuel millage on older.

 

the '03-4 have different ecms than the '04.5+
the turbo is different
the injector tips are different
pistons are different