[Def]

Obviously your alignment is off so when the diff biases(you get on the power), it's helping you go straight. I don't notice mine scrubbing any speed, as it opens up when not under power. When under power it biases the torque across the wheels, so if you have lots of scrubbing I guess it could slow you down some.

BTW - no need to break these diffs in. They're ready to rock from get-go and don't wear out under normal usage.