Gordon Kirby published
one of his typical 500-mile articles on the 2013 Cup cars. It's not just new bodies as this thread's says, but the car will get much lighter. Here's some quotes from the manufacturer heads:
"Because the cars are so heavy they have to build tires that can hold up to that. In effect what it's turned into is drivers can run qualifying laps every single lap and rarely hurt a tire. So they're throwing some major changes to the ratio of aero to mechanical grip and
let Goodyear work on doing some development to bring some tires that you can't run qualifying laps on every lap. So it will put it a little bit back into the driver's style and how hard they can push. If you overuse a tire you're going to pay for it at the end of the stint as far as lap time is concerned. "
So like in F1, Nascar wants cars that drivers can't run as fast as they could. They want drivers to drive slower on bad tires.
"We wanted to lock in the areas that we knew you could make big adjustments for big performance gains, but also
leave open the areas where it really doesn't matter. We wanted to make it so you could also put a lot of style and character into the cars."
What's the point of that?