Mine is a 3.31 car.

I drove a Roush R2 today with the Brembo's and 3.73. Meh. It has a $48.5k sticker. It was a 35k 301A rapid spec.

I have a tune so the test wasn't fair. But I felt nothing extra that I would want a 3.73 gear now.

I passed up a chance to drive a R3 with a supercharger. .
I wasn't going to buy it. And if I liked it, its instantly 8k for FI. It had 3.73 gears. lol.

 

I test drove a 3.31 but ordered a 3.55. If you don't race 3.31 is adequate but its clearly a ratio Ford used to meet certain mpg targets for PR purposes

 

I have no idea how big of a difference it feels having 3:31 gears to 3:73 gears. Compared to my 2:73 gears I thought I gained 100 HP when I got my 3:73 gears. Lol.

 

My wife's 11 GT has 3:31s and my Boss has the 3:73s. It's an apples to oranges comparison for the motor, but the off the line pull of the Boss to me is noticeable. If I start from a stop in both cars and rev through 1-3 to 3500rpm on both, I will be further down the road in the Boss than the GT. She's also got 18s vs my 19s for tires, which is also a factor, would be interesting to see the difference if her car had the Brembo pkg.