The cool thing about IRS is the ability to plant the tires without even haveing an LSD now if you add one it will really help. Think about it, the reason a live axle open rear wants to spin the right rear tire is the tq from the driveshaft is lifting that side of the axle and planting the other, with an IRS suspension the suspension moves instead of the whole axle picking up the right side. The lifting/planting action is lost in the CV axle. Even with no LSD they hook nearly as good as a straight axle.