Quaife (is the spelling) is what most people go for, unless you are made of money - then get the Gripper diff.
Quaife is fit and forget, so it has that advantage, but doesn't perform
quite as well as the Gripper.
For a track car, I don't think it's worth it. As a Burpspeed team member (oh yeh!) I've seen the time difference in races when they didn't have one on the car last year, to this year, where they have a Quaife fitted. Both Tony and Jay say it's great, and they definitely feel the difference coming out of the corners, but they are racing, so every second counts.
On a track car, there are much better ways of spending your money, namely more track days