The V3's have adjustable damping and rebound, so the ride quality is going to be varied, the V1's are just height ajustable, and they're hard.
Personally for slow driving and potholed roads, I wouldn't go with V1s unless you have a granite spine. If you're only driving in a congested place, I'd look at something with ride adjustment so you can find some some form of comfort setting.
As far as I was aware, the Weitec and KW kits weren't the same. The KW's are stainless while the Weitecs are galvanised. Is that it?