you need to start going there every day. not calling as that has just seemed to get them "another day". You need to take notice of stuff like where the parts are, what stage of install/assem. the car is in. This sounds like a bad run around.
He has the motor in just needs to put on the exh.?
he has the exh. but missing a gasget (what shot does not have a friggin gasket when they have had the car for more than 1 week????)
the guy got hurt, well that suxs if he did, but when I get hurt I still finish my JOB/WORK.
ALso make it clear that the shop has been very, slow and reluctant to get moving on your car while other people are in the store. Just happen to hang out in the waiting area/lobby and bring up how big a hassle it is. If they call the cops tell them the story and your there to watch your property/money and happen to have a phone bill that has the # of times you have called about the car. File a complaint and file one from every friends house so there are diff. numbers to the coplaints to make it look like a cronic problem. If you dont have a recpt./ and have paid for the service contact the law and a lawer for theft/excesive negligence(sp?) or anything else that might work.
QUIT letting them walk on you or you will go threw life letting things like this happen.