combat builds

Turbo charge with a high dps gun is pretty much all you need. If you really want to focus on the combat tree then concussive shot and barricade are okayish.

I enjoyed..
Turbocharge
Barricade
Concussive Shot

With all Kett Armor pieces.

Outside of Combat tree,

Auxiliary Systems Rank 4:
Weapon Mass Reduction for 40% weight reduction

Barrier Rank 5:
Biotic Alacrity for 10% weapon weight reduction and +10% movement speed.

I had four weapons and no where near going over the mark that it would affect my combat powers. Everything melted and I took the Team Support skills to be even tankier.

It's nothing flashy but you have a weapon for each situation. Barricade to set yourself up boost damage even without cover around. Turbocharge up as much as possible. Concussive Shot for detonation of ally's abilities or their special ammo.

It's really up to you if you don't want all Combat abilities but the power cells in SP are very limiting in the open world (the missions were well stocked).

Edit:
Btw, I know Barricade uses Power cells but I really didn't know what else to use while sticking to Combat abilities.