[@Darkmatter] via [@Ghost Shadow]
Is the city essentially martial law correct? All security is government controlled? 
Answer: Yep yep!

How hi-tech are augments and such that are freely available to the general populace?
Answer: Cybernetic implants are mass produced and used by just about everyone. Generally work done and come with many advantages but also have a number of side effects (See Science and Tech portion of the OP). More drastic modifications are of course from severe hospital care where the 'upgrades' are deemed 'absolutely necessary'


What would the government's opinion of private security contractors/PIs be?
Answer: Most private security would probably be owned by the ritsy rich who can get away with it. Government doesn't get involved unless they feel threatened