My sport button just makes the tranny shift a littler more aggressively...I have never noticed the suspension doing anything... She drives with it in normal. I drive it in Sport mode, with ocassional slapping the gear selector over into DS mode(my favorite ). I've used manual mode, maybe a whole 3 times.

In sport mode, the LED in the button SHOULD light up green, and there SHOULD be a "S" or "Sport" icon in the instrument cluster.

I was under the assumption that with the sport package, the suspension was not adjustable. Whereas non-sport based packages had the ability to change suspension geometry...