For all normal attacks, the damage is usually a range of values around your attack Stat.
Range vs armored will get you 50% less damage penalty
Body shot 50%
Body shot on Overwatch 50%*50% = 75% penalty
Body shot on Overwatch against armour = 87.5%
Crit will not suffer body shot penalty.
Have yet to calculate crit damage on normal and on Overwatch.
Have not tested crit against armor.