There's an online loading screen which describes LS Customs and I remember something along the lines of ''Chrome is class'' or ''Nothing like chroming your car''
Might be the bragging purpose of winning 50 races but that isn't exactly a big achievement. The reason for people chroming their car might also be because they think it's bling and because it costs a lot they think they're worth more meaning that they think that they're superior to others which is rather pathetic.
I mean, if things like these exists in real life, then it's no wonder it transitioned into the game:
The shocking part is that the owner and his friends actually believe that that looks good and they actually like it. Their parents were probably brother and sister.