I love my 3.73s. I still avg 22 mpg/tank of gas and it does help get ya going quicker. Better in town mpg too. You can't install gears alone and expect a world of difference, but they do help and with other mods it's sure as heck faster than crap 2.73s. There is alot of difference between 2.73s and 3.73s. I had 3.55s in before the 3.73s and don't notice too much difference but there is alittle even at that between the two. They are a must. Trust me and the others that WILL agree with me. $400 well spent on my stang. Man, those gears help the stang get the power out so much better than the stock POS gears.
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1996 Mustang GTS: 5-speed, K&N, removed air silencer, 3.73s, turndowns after stock H-pipe (no mufflers)