Let me tell you. I'd rather have shiny cars than ugly, dull, or even crappy cars. It's the same thing about G4TechTV show "X Play" sometimes. Someone comments about "shiny things." And I'm like, so what? I'd want some sparkle than dullness. I think someone joked about Driv3r in a magazine saying that "There won't be any shiny cars in this game..."
I know I made a thread about can cars sparkle, but the shiny nature of the cars doesn't mean they go faster, it just means they are presented nicely. With the right car color, the environment will be reflected on the car. So like the beautiful silver of the VW Beetle RSi, the car looks pretty nice when flying around Rome (like I did in a practice race). Even if ugly stock cars make it into GT4, they'd even shine despite the fact that people want to go wrecking them (I couldn't care less, really). So I'll put it like this. I'd rather have shiny cars than dull pieces of crap, like an unrestored car. But too shiny? Better than none.