Call up the BMW dealership and ask them what they'd charge for a head job and cam replacement. The BMW dealership should have all the special tools for your car versus a "might have the tool" independent garage. If the shop can't do a complete break down of costs, they are probably doing a little hocus pocus on your wallet. Anyways, if the cost of repairs at this shop comes anywhere near the cost at the dealership, why are you getting it done at this shop? You can always put the head in the trunk and have it towed.