: Find out what the delay is. Tell him no more of this end of the week stuff. You want to know exactly what he has left to do. Visit the shop more often if posssible and make sure there is progress. If at all possible be willing to take your Z to another body shop.
: See if they are a member of the better business bureau and threatten to go to them. Be prepared to follow through
Threats rarely produce the kind of results you want. Simply sit down with the man and ask him what the problem is. I could guess that by buying the parts yourself and saving all that money he may be upset that he did not get to make the profit he normally would have off the parts. Find out what the problem is, then take action if you need to. Remember the goal is to get your car repaired and get it back. Then you can sue the living daylights out of him if you want to!
