The normal aim maneuver adds a boost to the next attack and a second aim maneuevr adds another boost.
To aim at a particular part of a body or area, however, gives 2 setback. A second aim for that same thing reduces to 1 setback.
How would you rule the results of a successful attack, say, to shoot the blaster hand of a thug? Would one be able to make the hand drop the blaster with their shot?
What about if your player was aiming for the opponent's throat? Does that actually do anything special mechanically or is it entirely dealt with in a narrative sense?
Is it possible to perform both versions of aim in 1 turn? (Aim for boost, then aim at blaster hand for 2 setback).