Lowest accepted offer on Fannie Mae foreclosure

[Spencer Rossie]

What is the lowest accepted offer (percentage off asking price) you have had on a Fannie Mae foreclosure? 

I'm getting ready to make an offer 40% lower than asking price and want to know if I even stand a chance. The offer is justified, I'm not just low balling on a whim. I have had multiple contractors view the property and with the condition it's in (fully gutted) it's severely over priced. 

Also, will submitting any additional information with the offer such as bids from contractors, comps I have personally pulled, maybe even having the property assessed, be looked to or beneficial to my offer? Is there anything else I can do to increase my chances of the offer being accepted? Thanks BP!