I think you will be satisfied with either diferential you choose. I personally have had the Quaife for about 40,000 miles and have had zero problem with it. I don't think the difference in bias will be that noticable to you. I can just tell you that my Quaife never spins just one tire. I will also tell you that the only way you are going to go to the track and not spin your tires is to use a true slick and even then you will have to do other suspension work. I used drag radials with my Quaife at the track and still had tire spin with N/A 2.5 litre car. The installation will be the same for either differential, both are quality units, and either will be a big improvement in reliabilty over stock.
