westwest888

You get soft A4 steering feel and tons of understeer. What's the point of speed if you can't feel it in the wheel or put it around a cone? You need the sport diff to get the dynamic steering mode, which has much heavier feel.

Waudi

Yes for the price and the increase in handling..no way would I get one without it.

WatchNut

My S4 has the SD. I have also driven my friend's S4 which does not. And I have driven multiple A4s. Comparing the non-SD S4 is still nig and day versus the A4. Not the same animal at all. Acceleration and driving dynamics in the S4, even without the SD, is noticeably different fromany A4 that I have driven.

Think about the reverse of your analogy. Would adding the $1100 Sport Differential to an A4 S-line turn it into a S4? No chance.

AndyXXL

It all comes down to how you intend to use your car. If you track your S4 then I agree that sport diff is a must. For those of us that use our cars for our daily commute to and from work, sport diff is pointless, as I do not see too many orange cones on city roads and highways. I drive aggressively, very much so, but I don't need a sport diff to enjoy this great car during my 25 mile highway commute.

DrGP

Here's the rub. If you never had the sport dif, you will never know what you are missing. You don't know what you don't know

Excelsior7

A camry can do a 25-mile highway commute like a champ, too.

Now, I can't really say for sure, since I'm still in the "speculating on a purchase" phase, but it's my understanding that the Sports diff, by vectoring torque to the outside rear wheel in a turn, increases rotation and decreases understeer. Is it going to make an objective difference in performance? That's debatable, but I think it would make the car much more responsive when you're really pushing it, since not all of the steering load is on the front tires.

DrGP

Sport dif is also a safety feature since it send the power to the wheel that has the most traction. I believe it is up to 100% to one wheel. If you don't' get the sport dif, the S4 will still be a great car. Just not as good as with the sport dif.

AndyXXL

Yes, there are many cars out there that can do a 25-mile commute really well, but that's not the point. I'm sure you are not buying an S4 only for the sport diff, because there are many other advantages that our cars have over camrys, accords, etc. One of them is that they get to see your quad exhaust much more often than you get to see their boring rear end.

Excelsior7

My point was more that if we're talking about an option meant to increase performance in turns, urban highways maybe aren't the best way to qualify it.

WatchNut

...but you do if you've driven both versions on multiple occasions. In my case, that's true.