anyone tried these?

http://www.ebay.com/itm/Datsun-240Z-280-fits-R180-open-diffs-Limited-Slip-Differential-Conversion-Kit-/262292336254?hash=item3d11d76e7e:g:gyMAAOSwnDZT9CVj&vxp=mtr

Mickey Mouse POS IMHO. Don't waste your money...

Complete junk. Have a look what the guys on Hybridz have to say about them.

Can it be any worse than the OBX reverse installed helical setup? Properly rebuilt I hear it is ok....

These used to be called Phantom Grip.  I always wonder when companies change the names of their products.  http://3rdstrikeperformance.com/index.php?main_page=product_info&cPath=8140_144_10502&products_id=16749

It's probably "better" than welded if you want to drive it on the street, and just do an occasional two wheel burnout.  That's why most people limit their slip.

I limit my slip for other reasons both on the track and on the road. Burn outs isn't on my top five reasons.

I have had a Quaife in my street 240 for over 10 yrs without issue and am installing an OS Giken LSD in a front R180 diff from a 720  4X4 (4:38).

OBX once upgraded are acceptable but really, really loud. You truly get what you pay for...