After Inspection Counter-Offer Bluff

[Matthew Allen]

The inspection came back from a smaller six-unit apartment and 1 of 3 buildings need a new AC/Electric Furnace (Split Unit) with will cost $5,500 installed per unit, so basically $11,000 for both units. Both are working now, but are 23 years old and probably 8 years over it's prime.

The question that I have is... 

The listing agent has said that the seller doesn't have any appetite for fixes/replacements or concessions since I negotiated them down on price by 2.5% and negotiated a 4.2% owner carry contract versus 5.0%. 

Would you just move forward with the deal? Would you hold strong and command the concessions at closing? Other than these AC/Heating issues for $11.0k, the properties are flawless and in perfect condition. 

Thoughts?