You can probably forget about warranty coverage for this situation. Yes, the front of the PT isn't as streamlined as most of the vehicles on the road, but thats what makes it unique.
All you can do is preventive driving. Stay back from other vehicles on the freeway, especially trucks. Or buy a bra for your PT. At the end of the day, no matter WHAT you do, there will always be debris kicking up that can do damage.
By the way, my PT is Silver, which a lot of people had major chipping problems with (same as you describe on your Inferno). Knock on wood, so far so good after almost 2 years. Other than a few VERY SMALL chips, she's good to go
I also wax the bejeebers out of the front, not sure if that helps, but it can't hurt.
Good luck and happy cruisin'
