Can you define "much more"? One of the car mags did an article years ago and yes, the Dana and 12 bolt needed less torque than the 9". But, if it was a substantial amount, you can bet the guys running the fast heads up stuff would be running Danas and 12 bolts and the aftermarket support for them would be there too.
I believe if you making gear changes all the time, then the 60 and 12 bolt don't make as much sense, and they make so much stuff for the 9 inch now, alum reinforced cases, 40 spine axels and whatever gear ratio you can think of.
