373 not worth installing
Mileage not much different; although you notice the higher revs on the highway, esp if you have a loud exhaust.
Guy wants 3.73's, others chime in comparing other gears.
He wants some hard facts to go with the gears, which I already gave him.
My video will give him the go or no when I show him how they perform in a lid+gear only car.
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If you want to get new gears, get the 3.73's. No other gear comparisons matter because you don't have any of those other gears, and you can't go wrong with 3.73's they are the best for autos performance-wise.
Put this another way, I raced a WRX STi from about 10 mph roll....I was half a car ahead by the time we hit 60...I believe if I had had the 3.23s I'd have been behind by as much.. it just gets up and goes so much harder with the 3.73s.
IMO, 4.10's are the "best" gear, performance wise, for both A4's and M6's. But then again, it depends on what kind of "performance" you're looking for (and to what level).
1/4 mile? Street? Auto-X? Road racing?
Each is very different, and require different gearing.
For drag racing, 4.10's are great upto a certain speed limit, then you need either bigger tires, or a higher rev limit, or both to go faster. Then you'd need to drop to a different ratio if you're deep into the 120 - 130 mph range (that applies to both A4 and M6 equally, since you should be crossing in 1:1 regardless of which tranny you have). But for a stock-"ish" car, 4.10's will carry you across the line in top gear no problem
.I *personally* liked my 4.10's even more than the 3.73's I had for pretty much everything I was doing with my car at the time ... daily driving, and going to the track every now and then. Traction was no more of an issue than when I had 2.73's, and I knocked ~4 tenths off my 1/4 mile time!

This thread is/has gotten very confusing!!!!!!
You'll be happy with 3.73. If you did anything in the 4.xx's and do highway driving of over 20 miles, you'll be kicking yourself. I changed my highway driving habits with the 3.73's. Instead of going 75-80, its 65-70 and that makes up some of the difference and doesn't make me feel so bad about winding it out on the highway for hours on end.
1. How come noone ever mentions 3.90 final drive ratio (its always 4.10, 3.73, etc)
2. Why does it always go by final drive ratio, how come noone ever talks about, or changes the individual gear ratios. Eg. getting a longer first gear, having 2nd and 3rd a little shorter, having 4th slightly longer, etc etc
3. (thinking about starting a new thread about this one) These cars are known for torque and wide power bands with their big v8s and not having to whind the crap out of them to get power, unlike those high reving small displacement N/A engines out there (like hondas for example). So even though 4.10s have shorter gears, the gears are so short that once you shift ur still at around mid 5000's rpm or so, dont you want to be taking advantage of the low end power as well? Whats the point (from a performance/racing point of view) of having these big engines with a nice fat powerband if once you put super short gears in it your just using the last thousand and a half rpms anyways. Shoudlnt you want to use ALL of the cars widepower band?
By the way im asking more from a manual transmission point of view but the basics should apply to automatics aswell im assuming.


