Fire Sprinkler System

[Michael P.]

Hi All - I'm an investor embarking on a gut renovation/extension of a 2300 sq foot 2 family house to a 4100 sq ft 4 family house.  By virtue of increasing the units to 3 or more, I'm obligated to install a spinkler system in accordance with New York City code.  

I am looking for advice on what type of sprinkler system to pursue in order to be in a position to meet code while not blowing out my budget. 

Opinions on approach, systems are well appreciated.