Originally Posted by Classified
I think another indication of car customization would be that I have seen different rims on the vehicles in the game, as well as the Bull Bar on the black DeCLasse SUV in Franklin's trailer.
For all we know though, that's how that car looks as standard, it's the only one we've seen, but even if not, the Bobcat in IV was available in at least 4 different versions, with and without Bull bars and Spotlights, so these cars may just be alternate versions specific for V, rather than any indication to car modification at all.
Although, can you grab some screenshots of the same car models with different wheels? I haven't spotted that and it sound's interesting.