It's more like 35 hp steady speed down the highway. But the concept is correct, the power that is wasted in the differential shows up as heat. That's why circle track racers have oil coolers on their differentials (didn't want to say rear ends).

This rearend isn't broken in yet, just drive it for a while.

And I seem to remember the limited-slip manufacturers saying that the circles to right and left, the parking lot maneuver, is not recommended. It is part of the lore, but I'd listen to the manufacturers before folklore.

R.