G'day and welcome
The '07 ZX6 is a great bike as a tracky. You'll want to make some sprocket changes to suit whatever track is your usual track, and you'll probably want to drop the front a fair bit to improve the turn-in response. My pit crew can provide more details on that
I ended up giving my '07 tracky to my Pit Chief (I say giving, because he hasn't paid for it yet!) and picking up an '06 tracky as I prefer the front end handling, but to be honest there isn't that much difference between the two, and the '07 has a little more horsepower, even though it's the 600cc (while the '06 is the 636cc).
They're a great bike on the track, and nothing beats the feeling of overtaking 1000cc bikes on the 6's. The guys I bought my '06 tracky from took his 10 to the track and decided he had more fun on the 6, so went and bought a replacement 6 - they're *that* much fun

If you get one, you'll love it.
What do you ride at the moment?