Sport Button
 

I have a 2007 X5 4.8 w/ Sport Package. What does the "sport" button do besides change the gear shifting program? Does it, for example, stiffen the suspension or do anything else?

the ONLY thing it does is stiffen the suspension.

and holds the revs higher

No, that's what shifting the transmission into DS mode does. Sport button only adjusts the suspension.

X

suspension only, gearing is DS tranny setting

It also changes the sensitivity of the throttle response. It doesn't change the shifting pattern as others have mentioned. It's just the feel of when you press on the throttle. At least it's noticeable in my 4.8. When the sports button is pressed "on", then the throttle is immediate with the pressing of the accelerator pedal, but when the button is pressed "off", then it's just a tad slower. It feels like a slightly slower start as if starting in a higher gear.

The best way to exemplify this feeling is like starting your car from a stand still in 1st gear vs 2nd gear. Of course, it's actually still starting in 2nd gear (unless you move the shifter over to the left to DS mode) and it's as noticeable as this example. But that's the feeling.