i am interested too. however, and i am fearful to say this as it will most likely turn into an LSD vs ATB (or wavetrac) discussion but ... is it an LSD? looks more like a torsen/automatic torque biasing differential than an lsd, so begs the question - does it lock on braking, or if one wheel is off the ground? apparently the wavetrac atb has some features of an lsd while still having the low-maintenance aspects of an atb. real-deal lsds are in the +$2k range (eric has good pricing on a plate LSD here but still $1k more that this group buy) but you can get an atb in the $1300 range - still more expensive than the group buy, but a proven track record is something to consider given the significant cost of install.
http://986forum.com/forums/boxster-parts-sale-wanted/62603-anyone-need-new-os-giken-lsd.html