So I've never actually done anything like this before, but I was admiring the 1987-1991 Alfa Romeo 164 which was designed by Enrico Fumia at Pinninfarina.
In my opinion this is an absolutely gorgeous car. It's also non-traditional, which is somewhat common for Alfa Romeo's signature is their triangular grille. Another brand whose entire identity is attached to their grille is BMW.
I mentioned BMW for a reason. The 164 replaced the outgoing Alfa 6 which looked like this:
And here is BMW's 1986 7 series: Notice any similarities?
If I were BMW I might have sued them for the one on the left
which I bet is why they switched those headlights for the single squares and ditched the black in the grille metal.
The 164 looks nothing like a BMW, or any car of the era really.
I'm partial to sports-car trims like the red 2-tone example here with it's side-skirts and front spoiler.
But the 164 could also look rather conservative, and "grown-up" since it's an executive-class after all.
But This Brings Us To The Rear-End:
I've always felt the rear end was sort of mismatched.
It works fine for the less-sporty trims, and I will admit that on the sportier models it benefits from small additions like a spoiler, or the model decals/branding.
But I still feel like it's missing something, and I decided to add to the tail-lights a bit to see how it would look.
I started by just drawing them in, and then I decided to try and make them look realistic by clipping the tail lights and giving them shadowing. This is the result:



