[Dinobyte]

The time that has lapsed may well void any documented agreement of what was on the car. The new owner may want to check into the laws of his state to find out what the statute of limitation is for someone who fails to act on a claim.

Additonally, the Bill of Sale is the final document between the parties. Unless the BOS has a detailed list of the parts which were to be included, it may be difficult to claim otherwise outside of a small claims judge taking pity.

Another problem which was brought up before is the chain of possession. What was on the car when it was turned over to you, then turned over to the customer may be a sticking point and area of contention. If he claims that the parts in question were on the car when he turned it over to you, you might be the one under the microscope.