Interesting.... I don't find the stock suspension on the "6" too compliant. On my VW the stock struts were a bit too soft for my preference, and a set of Koni's tightened it up nicely without making it harsh when they got to the point that they needed replacement anyway.
So far the dampening on the "6" remains ok, but eventually I'm sure they'll wear out... it's nice to have choices. One thing I don't like with the Konis is that the cases rust like crazy compared against OE parts -- and I live where there's no snow!