I replaced the GIUBO "GUIBO" "Flex Disc" with one from URO parts (http://www.amazon.com/gp/product/B0066S2ROM/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
) , while doing my clutch. It seemed to be good quality and similar to the BMW one.
I followed the info I found on installing it correctly (Arrows pointing toward flanges, nut instead of bolt-head goes on back of flange, torque to spec from the nut end). It was a pain getting the two part driveshaft to stretch back to its original distance from the rear diff to the trans output, but no other issues. Even the driveshaft center balance bearing lined back up with where it was when removed.
I did convert to a single mass flywheel (lighter), so there is a little bit of vibration from rotation balance/gear chatter, but other than that I have no clue what the problem could be.
The fabric bands inside the guibo are starting to be pulled out in one direction. I attached a pic with the failure circled in yellow.
Any help is appreciated.