Get behind the wheel of a big rig and smash the living sh*t out of his daily driver. Then ask him if he thinks this will cause him any problem for the next two weeks!!! Ok, ok... seriously now, I think i would contact the police to make sure they had some kind of report about the incident on file. It IS their fault that you have nothing to drive and they have insurance just for that reason. I would get on the phone with my insurance agent to see if i had rental coverage and also make sure that the idiot owner would pay for all rental fees incurred for the amount it takes him to fix it. Once he knows that each day is costing him another day of rental, it may magically get done quicker. I would also have a few bodyshops that i KNOW do good work, look at the car and give you an estimate, then see if you have the right to take it to someone YOU trust, rather then making it HIS choice. What happens when you get your Z back and there's puddy 4-5" deep on your quarter because the guy told the bodyman to just slap it together because he didn't want to pay a lot of money for the repair? Another thing i would do is note what the odometer reads while it's at his shop. Lastly, once this is all over, i suggest you find yourself a new mechanic. This guy sounds like a real @ss. Just some quick ideas... good luck!