If you run on the street, you may be a good candidate for a TORque SENsing (TORSEN) differential. With a conventional differential, its natural tendency is to send power to the easiest end to spin. This is combatted by adding thicker fluid to make it divert power more evenly. A TORSEN diff does the opposite; it transmits power to the most difficult end to spin. The diff does this mechanically, by using a property of the gear mesh between a worm gear, and a straight cut gear. Fluid does not control the action of the differential, it is purely mechanical.

On smooth, high traction surfaces, this makes sure you get maximum power to the ground. The only time these are bad, is if you are on a rough/slick surface, where the differential is constantly struggling with which end to send power to, causing erratic handling.