So I inspected a 2005 ZX10R last weekend. I negotiated to $5K and took it for a test ride.
I did not buy the bike because it backfired a bit, and I don't want to inherit problems.
From the quick test ride I really liked it. Although it did vibrate a lot and felt heavier than my old R6 (which was only 1kg lighter on paper).
The low RPM torque was not as "incredible" as I thought.