The underside of a Gran Turismo 5 racer reveals this curiosity: the logo for die-cast collectible maker AutoArt (lower side, center).
AutoArt's made Gran Turismo models before (that actually is the Nismo Skyline GTR, the same car depicted in the screenshot), and GT5 studio Polyphony Digital has plenty of the collectibles on hand.
No one's suggesting they base the entire car on AutoArt die-casts, but it looks like at least a generic undercarriage from one was used here.
Update: Looks like this is an Easter Egg. Reader ShiryuGN supplies this picture of an actual AutoArt undercarriage; it has no logo, like the one above.
[thanks wh33z3r for the tip.]