If you really want to game the system, so to speak, there's a particular few things you need.
One is the Piranha shotgun. Research it as high as you can, and when you create it, put the plasma seeking bolts augment on it. What this does is all the pellets from the shotgun hone in on your target, and negates the penalty for shotgun range. The pellets cause just as much damage from range as they do close up.
Arms, legs, and helmet, research the Kett armor. Chestpiece use the Maverick armor. These all give gun damage bonuses.
Very important, find(if you want to chase after it)the Adreneline fusion mod. What this does is for a penalty to skill recharge(from 50% lowered to 25%, depending if you bought the right cryo pods), upon kill, all your abilities instantly recharge.
So, buy this point, if you have a level X Piranha, with the right mods and bonuses from passive skills, you should be doing a natural 1000+ damage per round, and that's without the 3 second damage bonus through the use of the Charge, Tactical Cloak, and Turbocharge. If you want to get really perverse, active Turbocharge, Cloak, then Charge at an enemy. Yes, all those 3 second damage boosts from Cloak and Charge stack on each other, which will, in theory, effectively give you 4000 points of damage for three seconds.
So really, can just chew through enemies, while recharging your shields to full after every Charge.
This build is almost unfair.