What I've noticed is that while driving at higher speeds (80+) on the freeway, with the sports button off, you feel slightly more lift when the road suddenly dips. With the button on (through the same section of road), the car feels tighter, stiffer and less bouncy. Not really a huge difference, but I like driving with the button on. Feels slightly firmer ride.

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2008 X5 4.8
White w/ Black Interior w/ Bamboo Trim | Premium | Sports + 214" | Tech | Cold Weather | Rear Climate | Premium Sound | Active Vent Seats | Heads-Up | Comfort Access | 3rd Row | Aero Kit | Huper Optik Tint | Clear Reflectors