The big draw of racing games is that you get to drive cars that you can't afford. But what about the cars that you'll never drive in the real world, price tag or not?
Video games are full of cars that just don't exist outside of the virtual world. You can make a good argument that the coolest of all was the Red Bull X2010, which only exists in Gran Turismo 5. If it existed in the real world, it'd probably pull so many Gs, the driver would need a pressurized suit.