I would get it notarized also Will, when you both sign it. Me personally, the only way I would go into it, is expecting that he probably wont pay without you getting it from him. So is it worth the hassle to you? Its nice to want to trust in people, but more often than not, you are let down. I would see if he will give you the title or some collateral of some sort. Either way, good luck and let me know if you ever want help collecting.