the only fighting chance he would possibly have (which still he has to pay) would be if no record of a discussion of cost (PM's could work as discussions) then the court could have an estimate of work cost made and force him to pay that ammount to get the car back. Nomatter what he will need to compensate the shop for atleast that value. and never know that value maybe more maybe less then the 16k but either way Joe you will need to pay something, signature or not