I have had this experience and this is what I did. I had a agreed price on the purchase and after the survey there was about $15,000 needed to be spent to get it up to the standard I was comfortable with. The motor mounts needed to be replaced and they and labour accounted for about $5,000 of that after they were replaced and the engine and shafts were re aligned. I took $10,000 off my original offer and would look after it myself or gave him the chance to fix everything on the list. He decided to make me a counter offer and I said no. After some thought he called me back and agreed to the new price. I was happy and he was not,but the decision is in your hands! I don't regret it and the boat was fixed properly and I know the work was down right! Good luck with your decision?
Cheers,
L