Just to expound a bit more on what I belive is the essence of the style. If we think of the early fifties when some of the classic cars were done they would use other components and accesories from cars of the same manufacturers ('52 headlamp rings on a 50 Merc)
In the early 90's when I purchased my Merk I did the show circuit and 2 cars stood out; Posies 37 3 window and ZZTop's Copperhead. These 2 cars were modified ever so slightly to a body style not produced that year (Phantom) As you walk by these cars they look like another hot rod then you stp and realise the subtilities. a 50 ford 3 window??, 16 in rims??, with a 312 Y block?? a TBird interior. As a whole the car is amazing yet nothing radical was done, the sum of the mods make it extraordinary.
That sound like something the PI members do to their Pantera or even a Mangusta without fear. Change the signal lights, or marker or taillights, or the grill work, or gauges, or seats, maintain the essence of the design without being radical.
Denis