Glad your G80 is functioning! As for how a limited slip works, most use a series of clutch plates compressed by a spring. When one wheel starts to spin faster than the other, the plates on the opposing side are compressed to attempt to transfer the torque to that wheel.

As for lockers in the front diff, I've only heard rumors that they can crack the diff housing due to the stress put on the internal components. But maybe someone else has actually seen it happen?