I have a passenger front where the battle of the rot is being lost, while up at a scrap yard i found a prestine Gen 4 door are the doors as a whole interchangable? Plus i loke the gen 4 doors better have better pockets and handles
The door panels won't line up with the dash and the colors won't be the same if that bothers you (assuming you're talking about keeping the G4 door panels, since you said you like the handles and pockets).
To use the G4 doors with G3 door panels you'll have to drill out the rivets on the interior door handle to install a G3 handle. Also, late-build '03s and later have different exterior door handles - earlier G4s have the same handles as your G3.
yes replace the whole door. no other way. but if u don't mind the interior not matching or lining up then there are no other steps to take. if u want to keep ur interior then u will have to do the steps mentioned above.