I think the only major difference between 3.73 and 4.10 is the fuel economy. I wouldn't get so hung up on whether you got the deepest gears you could. Gears can only do so much. I've not seen 4.10s hit the 12 second threshold, but several 3.73 geared 3.7s have. I've also only heard of one guy with 4.30s and he has trouble with getting everything to work right.