I would take everything valuable out of the car and leave the doors unlocked. This might sound ridiculous, but I've had to replace many Cabriolet tops by someone really wanting what I had inside my car. Usually the thieves will use a knife right above the drivers window to gain access to the inside. I've used duct tape to patch the top, but know I just leave the doors unlocked, pull out my backpack with the removeable radio and don't worry about it. My car has never been broken into or vandalized since (going on 3 years) or maybe they have opened the doors and didn't find anything and left.