How Did Active Roll Stabilization Work and Evolution of Sport Package

Two questions:

1. My 2006 550i CPO included Sport Package. According to window sticker that $2,300 option included sport suspension and "active roll stabilization." How did "active roll stabilization" work--i.e. did shocks stiffen up when sensors detected roll or are there some hydraulic systems that actively work to counter roll or just stiffer shocks or???

2. Has Sport Package option evolved since 2006 so I will have to look for other items beyond just Sport Package if I want "sport suspension" on a newer CPO? For instance, on BMW website looking at 2011 550i which lists Sport Package as option. But unlike my 2006, description of Sport Package option on the 2011 CPO does not seem to do anything to suspension (except tof wheel/tire)--it mentions only (1) 19 inch alloy wheels, (2) sports leather steering wheel; (3) multi-contour front seats; (4) shadowline trim; (5) increased top speed limiter. No mention of "sport suspension" or anything related to handling.