Zenmervolt
Elite member
Get the tallest gear you can. You'll appreciate it on the highway. Unless you're going to race you don't need the shorter gears and will regret getting them most of the time.
With a 0.65:1 overdrive 6th gear in the Mustang there's really no reason not to get the 3.73 rear end. The overdrive ratio in the transmission itself is so ridiculously tall that even a short final drive like a 3.73 is still going to yield relaxed cruising on the freeway. Remember, even with the 3.73 rear end, the GT still only turns 2,000 RPM at 70 mph; that's pretty leisurely for a sportscar.
ZV