I didn't like the hunting feeling through the steering wheel on ice and low-low grip situations. It wasn't just the Quaife that exibited this, the OBX diff does it too. As mentioned above, Very slick conditions or wheel in the air situations allow a helical diff to act as an open diff. On tarmac though, when you turn into the corner and apply power again, the front end pulls for the apex, instead of pushing out. You are able to get on the throttle much sooner, and increase your exit speed substantially.
For your power levels, you'd still be fine with the Quaife. It's made from very good materials. You will want to take advantage of the rear grip though, as that much power will likely spin both front wheels exiting low speed corners. A DCCD will exponentially transform the car and tie the front and rear diff setup together beautifully.