Diff gear recommendations

Thanks Rob, adding a 4spd hump wouldn't be an issue. That would be hidden with my auto console anyway.
I just hate to cut and mod. I'm getting to an age where I would have to sell it in not too distant future and want any changes easily reversed back to original.
With no tunnel modifying, you're limited to the A833OD 4 speed. And if you don't have a four speed hump, then you have to modify the floor. There is no auto OD that fits without mods. Not even the GM 200.