Good choice you can always change them at a later date but i am sure you will be happy with them and the added mpg enjoy

 

I've got the 3.73s and like the low end grunt - since the car only has 340Mi on it I'll chime in later with a more refined opinion. I coming from a 07 LS2 Corvette, the lower gears make the car's off the line feel similar to the vette. The real world mileage will be intersting to see. The Corvette was almost always dead on 17.7MPG average for me (daily driver) as will the Mustang will be...

Developing...

 

My '05 had the 3.55 and I was pleased with them. This '11 has 3.73 and I really like it. I'm a little worried about traction when I put on a blower, but I'm not going to lose any sleep over it. Either way, 3.55 or 3.73 you are a winner.

 

Well mine is a 2011 GT Brembo w/. 3.73. Very fast car, you will see a very divided opinion, but I think folks at FORD, know something because the 2011 Shelby GT500 & 2012 BOSS, both come with the 3.73

 

Just to clarify, the '11 GT500 w/the SVTPP comes w/the 3.73s, non-SVTPP still comes w/the 3.55s, but I agree, it is the new signature gear for their higher performance packages...

 

I have seen it posted a lot about the shelby using 3.55 as justification for using it on the GT. They use 2 diffrent powertrains. Its not just the wheel size that makes a diffrence, its the powertrain.

 

Naturally aspirated Mustangs or those with centrifugal blowers (or turbos) work best with steep gears (4.10's or more), while those with roots/twinscrew blowers work best with less gears (3.55's or less) due to their abundant low-end torque. 3.73's tend to be a good comprimise for any setup.

 

I had my 3.73:1 equipped car for a few days now, and I'm seeing a max highway mileage (in 6th) of about 23 MPG at around 63-65MPH... Any faster and the mileage heads south. I expect I might see another couple miles per gallon once she's completly broken in. I got about 450Mi on the odometer at this time.

 

I did a little more research and with 1st gear so short, it seems like it'd be more than I want to go with 3.73 and I even debated going back to 3.31 and saving the $340 on the order. With 3.62 first gear, 3.55's up it to about 3.90 and 3.73's take it up to about 4.11. I don't want to be starting in 2nd gear, as I don't see a point in that for daily driving. I wanted a 6 spd for that very reason, to have few acceleration gears and an overdrive 6th, not change the car to basically a 5 spd all over again. I even worry a bit that 3.55 could be a bit overkill in 1st gear.

 

You're worrying for naught; I have 3.73's and 1st gear is plenty usable. I normally gear up my cars (4.10's or 4.30's), but I think the 3.73's in my '11 GT are plenty of gear with the 6 speed trans.

 

I love my 3.73 gears! Its what sold me on the car. I first test drove an automatic with 3.31s and was thinking that I wish it had a little more throttle response. Test drove one with 3.73s and placed my order the next week. I drive around Atlanta which has a lot of traffic and the 3.73s haven't bothered me at all. But this is more of a personal preference.

 

I have 3.55s and like them, but at times I wish there was more low end grunt when in 6th gear. However, I am not sure how much difference 3.73s would really make since there is just a 5% difference. I do like the 3.55s when cruising on the highway. Again, I have never driven with 3.73s but I would think the drone you hear at 70 with 3.73s would be equivlent to the drone at 75 with 3.55s. Around here the traffic regularly moves at 75-80 when not rush hour.

Like many others have said, you can't go too far wrong with either but I definitely would not want the 3.31s.

 

I got my '12 with 3.55s and I don't regret it. I think I'd be shifting too much for my preference with 3.73s. Of course, the important word in that is "preference"; it's yours that matters, and nothing else.

 

I have 3.55s....and as I have said many times, I'm happy with them but I guess I don't really know what I'm missing.

I do know that I get between 22 and 26mpg (well, 25.77mpg calculated was my best) and I think the extra 5%-10% mpg will help out a lot this summer if gas hits $5/g.

If this car was purely a toy rather than transportion that I'll be paying for over 5 years, I might have opted for the 3.73s...but the 3.55s were a great compromise, IMO.

 

You would be hard pressed to feel the difference between a 3.55 gear vs. a 3.73. The difference is to minute.

Dave

 

I love my 3:55's, awesome low end grunt and good gas mileage. Cant beat that imo. Either gear you choose is going to be a winner in my book.

 

I think you all may be right. I'm still a nerd at heart, so yesterday I 'built' my exact car on my xbox and spent plenty of time driving around at normal speeds and going for track records in all 3 gears. 3.55 and 3.73 are very close. You'd be surprised by how much help that can be. I've got accurate gear ratios for each gear and you can just change the final drive on each of them. I'm sure I was worrying over nothing. I just didn't/don't want to regret ordering the 'wrong' things on my '12. On a side note, I added the Brembo Pkg, and my Priority dropped from 10 to 13 now. My own fault I guess. I know the dealer is hopping busy as well.

 

Less 1st to 4th nanny interference with the 3.73's.

 

Are people still talking about skip shift? I have had my car since august and it hasn't bothered even once. Actually, I intentionally do the skip shift more often than the trans does it by itself.

So... you may be right but I think that it's absolutely nothing to worry about.

 

I feel like a chump with 3.31's!