I only know about the things already mentioned, lack of a LDP, different charcoal canister, and may some fittings on the manifold which I will check later.
One thing that is very odd but very helpful is all of the holes for mounting stuff for the 97 and 98-06 inner fender crap are still there. I'm using a set of late model fenders from a Rubi and they have the same holes for the PDC and later square charcoal canister mount.
If someone wants to post up a pic of their PDC bracket, my 97 is the two finger mount, later ones are 4 finger but I don't know if that is a 97 only thing. Has to do with on some at least if the lid opens from one side or one narrow end.
Has anyone mentioned the rubber grill trim near the radiator yet?