Clutch-type differentials are lighter and more aggressive than torque biasing differentials. In high-horsepower drag racing as well as racing on loose/slipperly surfaces, nothing can touch a car equipped with one of these. The traction advantage is so significant because the torque always goes to the wheel with less slip. That's even if one tire is on an oil patch in the burnout box, spinning on glare ice, or is completely shredded! (Helical diffs only work when both tires have at least some traction. Without it, the diff goes completely open.) Driving characteristics are somewhat odd on the street* but the feel is pure magic in hardcore competition.
Special note from Scott F. Williams (USRT rally driver, ret.): "Recovering from a near spin on gravel with an open differential is almost impossible. With a helical-type it's difficult. It's almost a certainty with a clutch-type diff. Countersteer, boot the gas pedal, hook up, and hold ON."
*Note: The new "SUPERQ" technology offers some wonderful new benefits:
A) Reduced/nearly eliminated chatter (Less complaints from the wife...),
B) More linear engagement/smoother torque transfer (Easier to drive at the limit),
C) Superior heat resistance (Doesn't overheat and lose torque biasing capability),
D) Advanced compound (Last longer between service),
E) NO BREAK IN (Get in it and drive immediately).
Package contents: Kaaz differential, gear oil, ring gear bolts