I haven't heard anything that relates this issue to the coilover itself.
There are definitely much stiffer setups being run on other CO's
TCKs & GC for example can be ordered with much stiffer springs than KW Clubsports.
My Clubsports are definitely softer than the GCs that I had.
IMO, car usage is probably a more important factor than the CO itself.
Also related to this topic;
it has been speculated that using a STB helps.
Supposedly the ring on the top adds stability to the area.
I haven't looked for a long time, but there also used to be reinforcement cups available to strengthen this area.