I've always used a good real estate lawyer when I sell. Though I've never had such an expensive issue like you, I've usually done the fixes and then just added it all onto the cost of the house and have ended up winning. Because when the bank comes and does the inspection for the potencial buyers loan they are presented with all the paperwork and bills of all the updates and repairs done on the house since I've owned it and easily justify the cost. If I have to fix anything I won't budge much on the price. If it can't be sold "as is' then I'm not gonna loose if I have to invest more. On my last house sold I made over 10K in repares and upped the price by 30K and made a 20K profit on top of what I made selling the home! Thanks to the advice of my realtor I hired I did what she suggested but then when she tried to quick sell the house to the buyer I said no to his offer and reminded her of what she initially told me to do. I did it and now this is my new last price! The buyer somehow found the money and bought at my price. Good luck with your sale man!