Hi Mickwitchy...!!
I have installed the Annitori Quickshifter on both my 2011 ZX10's and they work perfectly.... Especially the track bike... you think you can do a clutchless change and not lose any momentum.. well when you have the quickshifter fitted, it is so smooth and seamless that you actually continue to acellerate faster each gear change... you will love it, especially when racing and getting away at the start.. (or even at the lights on the road)
No problems at all with the down shift... it wont cut the bike out.. I still downshift the same way and blip the throttle when going down, but it is just as smooth and it is best if you have the QS set on the hardest setting....
Some problems that Annitori will let you know about are if you have a habit of resting your toe on the shifter or having your toe touching the shifter getting ready for a change, you will just have to break this habit and become more precise with your changes, as the QS will be thinking that you are trying to change gear and it might jump into gear earlier than you wanted.. or not change at all.. SO basically they are saying to keep your toe away from the shifter until you want to change.. keep the throttle on then touch the lever and BANG it will change with no problems at all. This is not a problem with the actual QS, it's just a bad habit that some riders have and you have to modify your riding slightly to make it all work smoothly. It is perfect and a definite bonus on this bike.... I highly reccomend it...
My first test at the island on the track bike, and I dropped almost 1 second immediately and my top speed was higher.. faster in 2 sectors and this was just from the QS.. as I got better at riding the bike and utilising the QS I am just getting faster...
If you have any trouble fitting it, let me know.. it is very easy to do...
Macca