Great question you have about whether to deal with the laws in the state in which you reside or the state in which the contract was signed.  First, look to the contract that was the subject of the repossession.  There usually should be a jurisdiction provision.  If it mentions that the contract must be reviewed under a particular state's set of laws, then that set of laws applies.  If the contract is absent on that language, you use the state in which you signed the contract.