Lots of sage advice Jo. My two cents? Wouldn't build it for a friend or a stranger, too many potential problems. There's not enough incentive or legal armour-plating to cover your arse. You build a vehicle to his specs, you assume responsibilty for it's driveability and his safety. You sell a vehicle already built, even with many custom features, and it's "buyer beware". The difference is he contracted you to build him a safe and reliable vehicle versus buying one that is completed, putting the responsibility of a thorough inspection on him...just sayin'!! Best of luck no matter what your decision.