The KW v2 is exactly the same as the FK Konigsport damper, they both use the Koni insert and a 60mm coil spring so if the FK is cheaper then go for that one.
The normal FK highsport isn't adjustable so your just going with whatever damper rate the factory set (not high enough if you ask me). Not sure on the standard non adjustable KW, not tried that one
Barbz was running a set of FK's with a piar of koni inserts I originally ordered but I ended up getting a set of Leda's instead.
Mine have not corroded though and i find the ride quality is vastly superior to the FK Konigsports. Anyone who has standard or Bilstein+Eibachs is impressed with the ride, body control and high speed stabilty.
I think they are worth the money, and the damping adjustment range is quite wide, you can really soften up the front of the car which makes the ride alot more enjoyable on bumpy country roads.