I would def go for for KW2. I had it on my previous 8 and i loved it
The adjustable Koni shocks in the KW2 kit is perfect.
I have B6 on my S8 now with oem springs. Works perfectly for everyday use but i would like it a bit stiffer. And the B6 is NOT for lowering springs, then you need the Bilstein Sprint that is Shortened. Had those on my S6 for several years and that was great for racing/trackdays.