Since the early 5th gens have very similar engines, would the Injen from a 4th gen fit directly onto the 3.0 5th gen motor? I want to buy a 2K/2K1 and it would be nice if I could keep my Injen and swap it right to the 5th gen.

 

Everything will fit in both engine bays. The only thing is that the 5th gen has 3 breather lines that are connected to the front of the tube after the MAF. I don't know 4th gens setup in that area but I know they are different. You would have to modify that area or at least run a filter for your breather instead.