3.55's instead of 3.73's?
 

I have a 2013 GT, Manual, with 3.31's. All the mustang's I test drove before the one I currently own had 3.73's and felt a lot more powerful than this one. I have been looking to get 3.73's installed, but hear a lot of people complaining about how 1st gear is too short and bad fuel economy. Currently 3.55's are on sale this month from http://www.americanmuscle.com/yukon-355-1113gt.html for $130. Does anyone here have 3.55's? What do you guys think?

Going from 3.31's to 3.55's wouldn't make much of a difference and really doesn't warrant the cost. If you haven't gotten a tune then that would be the first thing I'd do.

I have 3.73's and love them. Yes, 1st is a little on the short side so I mostly take off in 2nd in traffic or flat ground. I also did not buy my GT with MPG in mind. Just does not make sense to me at all. A performance car with great MPG?? Any way scottmach is also spot on with a tune first. 3.31's actually seem to well with the MT82 & 5.0. They are a lot better with the 5.0's than with the old 4.6.

my '13 GT came stock with 3.55 and 1st is still short imo unless you like shifting at 4k.. My setup is a tad bit loud lol 90% of the time I usually just use 2nd gear to start unless on a hill or at the track.

Just seems to defeat the purpose of having a 6 speed if you are going to start in 2nd all the time! Ugh...I don't know what to do.

I think you cant go wrong with either, I have 3.73's in mine and dont mind it at all. The only thing I dont like is that with the stock Pirellis with the 3.73's I can barely get on it in 1st or 2nd without it braking the tires loose (Heavy right foot).

The big change in MPG will be more from your right foot than any where.
Like Scottmach said if you are willing to consider a tune, that willy really wakes the car up.

I have a fairly heavy foot so when the light goes green I tend to giver and so with 3.55
1st seems hella short. That being said the MPG is all how you drive.. I run a 93 race tune daily driver and in the city I see between 12.0-12.5 l/100km (18.8 - 19.6 mpg for my american friends) and highway I see 10.0 - 10.5 l/100km (22.4 - 23.5 mpg) and on the highway thats doing 120 - 125 kph (approx 75 mph)

If ppl call that bad fuel mileage then either they smoking something pretty good
or they are Torretto wannabes and doimg 1/4 mile runs at every light...

+1

I have 3.73 in mine and wouldn't think of another option. It's truly the best all around gearing tons of pull while still offering a comfortable cruising. Again didn't buy a Prius I bought a Mustang. I average 17mph city and 22 highway not bad at all IMO. Don't talk yourself into anything lower, the small change just is not worth the $$. You stated you test drove cars with the 3.73, and your looking to change.. It's all going to be compared to that. So if you go lower, it won't compare and your ultimately are going to be disappointed.

So I shouldn't let the sale price sway my decision?

I wouldn't let the sale price sway your decision. I too have 3.73's and the car pulls so hard in 5th gear. I let a buddy of mine drive it and he was in shock of how much pull the car still had in 5th. That's what 6th gear is used for, crusing down the highway at 70+. at 83 MPH I'm turning 2500 RPM. I wish that my car came stock with 3.31 that way i could see the difference between the two. Also, if you like to drag race I cross the line topping out 4th gear without having to shift to 5th.