[driftflo]

the holes improve oilflow between the clutches. so the transition from lock to open and vice versa will happen smoother. the car behaves less aggressive without compromising the (locking) performance.

you can save ~10% of weight compared to the OE LSD. and as this is rotating mass it does add some small amount of performance. not much, but it is a nice side effect you get while improving the lsd performance.

OS giken is even heavier as the OE unit. drexler slightly lighter. the lightest core is the bacci romano one but this one needs special output flanges that do add some weight again. and it is not capable of taking so many clutches as the drexler does. so you could make the drexler a little lighter still if you remove some internals (that would downgrade the performance)... so that does not make sense!