I carry a thin wallet in my front pocket. My legs are essentially straight when driving ( a little bend of course, but I don't keep one knee up ) although I will shift positions a bit from time to time. That said, the lumbar support in these cars is non existent. My PT Cruiser has a terrific adjustable lumbar support and I feel great after driving that car even after a 9 hour drive. The Crossfire will kill my back in 45 minutes.

I've also got a small lumbar pillow that I use when driving, even if I just take the car to work one day. I had one of those inflatable lumbar supports that 32krazy! mentioned in my old Miata and kick myself for not thinking to keep it when I got the Crossfire. Oh well. Worse things have happened in my life!