Since we already have a basic system of bionics in the game it seems like a good idea to expand it a bit.
They obviously should not be cheap, but totally worth it. Like, getting new arms would give you the "strong" trait, but for a lot of money and small debuff for a day or two (since our character isn't used to having those yet).
Maybe you could get "tough" by implanting some armour plates inside of your body. It would obviously make our character a bit heavier and affect the carrying capacity.
And it probably could be fixed with bionic legs! They should give you "athletic" and increase your carrying capacity (since, well, bionic legs won't get tired as easily).
It shouldn't be too hard, since we already have a similar mechanic with the eyes, but I'm not a professional, so I might be overlooking something.
I may be stupid, but I'm not dumb.