Hooah to that. The auto may feel a little crack throttle soft on 3.15s but when you hammer it, it'll blow tires off all day because of the steep gearing in the box.
I'm keeping them because I have torque in a bottle and will probably go FI again down the road so, I don't need more gear.
But wait, I shoved 4.10's into my 1956 Ford pickup and it made a HUGE difference. Isn't this the same thing?