I like my Koni Sports with H&R -30 mm. They're comfy enough for me. I don't know how the B8 would be like so I can't comment.
If you know the KW Clubsports are what you really like and you can't get any GTI with the other suspension options to try out, I'd go for the KW.
My Koni Sports cost 464,40 €, much cheaper that that price you mentioned for the Bilstein B8. I think you can get the B8 from Germany cheaper than £ 600. Around 500-550 €, maybe.