I do understand it's based on the art, but the colorway makes me think that its missing out on not referencing Midnight Purple, the unique color that belongs only to the Skyline GT-R family.
Also sad to see no novelties.
Some ideas:
Single - "S" emblem found on 32 hood (bonnet), side "GT" emblems found on fenders
Spacebar - GT-R logo in the middle, 33, 34 grill style
Shift - GT-R Tail lights, "V-spec"
Numpad - Shift-knob style