What gears to choose
Hi, there is some difference between the 3:30 gear range and the 3:73s but a couple of mags posted articles several years ago about testing the GT Mustangs with 3:55s and 3:73s in a 1/4 mile and there were no differences in times. This is understandable as they are so close. About the only way you would see a difference is if you had the gears in a Nascar car and at 150 to 180 mph you would possibly see a slight difference in one car over another with the different gears. But, since Nascar tells you which gears are allowed I don't see that happening. At least the last I heard all the gearing was chosen by Nascar.
Anyway, back to your car. The change from the stock gears to the 3:30s would be a very nice change for you without hurting milage much. You will like the difference in the feel of the car as you depress the gas pedal. I don't think you would need 3:55s unless you want to be more aggressive. That's just my 2 cents worth. Mike.