the way i see it, the best rear end to run is the one that best matches your combo or trans gears, intake, cam, power range, etc etc, no matter what car you are in. you run a 3.54 with a mild motor, like mine, once you run that crazy lift cam and the big high manifolds, your low end will be sorely affected by those 3.54s, and that power will be of no use to you on the street until way up high, and you will be slower light to light.
yes 3.36 or 3.15 is great with no overdrive, but who here built this car to drive to work on the freeway everyday, and can i get a show of hands for the people who built their ride for performance??? your whole combo should reflect what you are trying to do with the car. no overdrive and 3.90 or numerically higher, your top end is affected but it works with radical combos to make the most useful power the way its supposed to. i dont have an overdrive, and i run a 3.54, im slow on the freeway but its fine, i drive slow in general until its time to rock. if you build a crazy motor that makes that mid and top power, i believe 3.70 and up is in order to maximize your ability to use that power, isnt it?