The problem is that "conforming" loans (conventional loans that can be sold to Fannie) have a cap of $417k and as you know there aren't many of those in NYC. 

Thus most loans need to conform with Frannie/Freddie rules.Local banks will likely charge less points than brokers, so that is what I use.

For them to do this they have to conform to a set of rules, and are called conforming loans.With a portfolio loan, there are no rules.  

Ask to see a quarterly report from one of their portfolio properties and see if it presents clear, concise information and appears to conform to common accounting standards. 

I've seen non-conforming properties sell for quite a bit less than their comps if lending is not straightforward.If it were me, I'd do a cash-flow analysis based on market rents and high maintenance costs, a comparative analysis as SFR's less the cost of getting it there, and a comparative analysis as a 4-plex and see if the numbers converge.If you do make an offer, give yourself plenty of time to do due diligence to figure out what you've got.Good luck and keep us posted.

You need to find out the use, what is permitted, non conforming etc. 

What are some options you have with a non-conforming unit?

As you figure out how to manage subs, try to call others back who messed up, reschedule others who walked off to do another project because the work wasn't in conformance to accept their work, rehire new subs because others who just disappeared because you paid them already and they are cheap "trunk slammers."

I am from Philadelphia and my landlord from a few years back bought a property and decided to tear it down... the city allowed him to do the demolition, but did not let him rebuild because it was no longer a conforming lot. 

I do not see any electrician not recommending an entire electrical system overhaul or replacing everything as a new code conforming installation which by the way will need both permitting and inspections.