Is the squeak coming from the door panel or from the actual door itself?
okay, thats not a terribly un-common problem you can get a product called gummi-pflege that should cure your problem. It is made for lubricating weather-stripping and works well for silencing squeaks such as yours. you can normally find gummi-pflege at your local BMW dealer, but the porsche dealer may stock it as well.
If you cannot find any, a company named Wurth makes a product called rubber care gel that works well, but doesn't last as long as the gummi-pflege.
I wouldn't think your squeak would be the result of a wreck either!
ASE Certified Technician
I have 8 years of experience and specialize in high end euro cars.