[jmatta]

Those things are a pain in the arse. Every Porsche I've owned came with some kind of lock nut/bolt and I immediately replaced them, just to avoid a situation like yours. Just bought my son a Jeep Liberty and even it came with silly anti-theft bolts...gone the next week.

I've heard the socket tool that graps the bolt is pretty effective...take great care not to damage the wheels.

Good luck!