Just looked at some of my notes on the KWs.
Referencing the picture below, comparing the KW with a Boge, which I'm guessing is about the same as a Bilstein (sports may be 20mm shorter):
The extended length of the shock from the center hole of the lower mounting outlet to the top of the piston shaft (as it steps to the threaded rod portion) is 22 7/8" on the Boge, and 21 1/8" on the KW. The bodies are about the same length, just the piston rod is shorter on the KWs. That is a difference of 1.75" shorter on the KWs. On the KWs bump spacers, you can see two hard rubber spacers 0.6" thick and a soft yellow bump stop 2.1" thick. On the Boges, that big black rubber bump stop is 3.75" long. So the KWs are already designed to further increase travel by 1.75+(3.75-2.1-0.6-0.6) = 2.5" before hitting the bump stops. In addition, if you were to remove each of those 0.6" hard stops on the KW, the piston further travels without bottoming out, even with all the spacers and bump stops removed, so you could remove one, maybe two of them for further travel. On the Bilsteins you could and should cut that thick rear bump stop some on lowered cars, I forget how much, but you could do the math on that:
The fronts, they're shorter too than Bilsteins, but the only notes I have are that the length of the damper body from the center of the lower eyelet hole, to the top of the cartridge body is 393mm. and that the shock travel without any of the bump stops or spacer 143mm, so total length from eyelet to top of the piston shaft right as it changes to the threaded rod, is 536mm. Also if you were to remove all the bushings including the bump top, the piston will not bottom out in the cartridge, but don't attempt to do that or you can push it in too far and will blow out the oil and gas shock at the top as the rod steps down to the threaded portion! (believe me!)