NOTAR's are quiet....maybe a swarm of them rather than a single aircraft doing the mission....also allows for one aircraft to cover the other if guns are carried....think mini-gun...not GPMG's or M-240's.....depends on the mission, mindset of the outfit....flying around a built up area is filled with peril....low invites small arms fire....high invites one of the 5,000 missing MANPADS....personally low and fast as heck might be the right answer....particularly at night on NVG's. They cannot see you...they cannot shoot you. Do remember to turn the stobes off!