I can remember someone doing this to a 93 GP 4-door years ago. IIRC, they used the older non B4U style parts (91-93), used the front bumper and the rear bumper and considering it didn't have the B4U side moldings, it blended in well and looked good.
I'd vote, if you love the car and are willing to spend the time and money, do it! Be one of the few that have done it.
By the way, i'm talking about this style non-B4U. B4U would be too much work because you'd have to somehow blend in the fiberglass flares into 4-door moldings.
