I've never ridden in an xB on stock springs. From what I hear, however, the car rides like a skateboard no matter what you do. In this respect, an air suspension setup actually would help, as when the car is lower, there's less pressure in the bags that hold the car up, and thus, a softer ride. Additionally, Monroe shocks apparently make for a smoother ride than stock, at least enough to offset the use of lowering springs.
__________________
|