Right, I understand the mechanical advantage of lower gears for accelerating, but once you're up to speed the engine doesn't care how cruise rpm is maintained, 2500 rpm is 2500 rpm whether it's accomplished through OD and 4.30s or Drive and 3.73s. The trans is essentially doing nothing in D and lockup so there is relatively no heat buildup in the trans. I just don't see the logic of dropping hundreds or thousands on a gear change. It would be different if it had 3.08s or some horrible highway gears, but 3.73s are not stressing the engine or trans on acceleration at all.