I would let him/her cool off. Ultimately it might not even be your call that he's/she's upset about.
You already said you'd eat the motor, so you have to stick to your word on that, but he/she approved the 1160 and should stick to his/her word on that.
Just something I learned along the way, depending on the person sometimes too many choices aren't good, they hear what they want and some won't ask questions, but they think you're trying to confuse them. Keep it simple... If they ask what options are then go there.
FWIW, seems like you tried to do them a really good deal and provide quality work with complete transparency, so if they don't see the value in that, it is on them, not you.
This completely ^^^^^^^^^^^^^^^^^^^^^^^^
" FWIW seems like you tried to do them a really good deal and provide quality work with complete transparency, so If they don't see the value in that it is on them not you".