As stated by many...the bike shifts best by only slight clutching, and slightly coming off the throttle,, and in fact, if you do as described with the upward pressure preload, you don't "need" the clutch at all to up shift, nor do you need the "quick shifter". You only have to roll off the throttle enough to come out of acceleration to do this. If you preload the shifter, once you come off the throttle slightly, it will shift right up smoothly even with no clutch.
That said, I have the GSA on my new S1000R, and it is sweet. Wish I had waited one more year to get the GSA Pro, as they added to the 17 Single R. I have experienced the GSA Pro on the S1000RR and it is even nicer being able to downshift without clutching and exact rev matching.
Yes, this is a feature that should be added to the K1600!