OK I was not going to harp on this much but here goes. I had my suspension upgraded a few years back. New B&G springs, Billy's (Sport) IE sway bars. So the negative camber was bad (-5) but you know I lived with it. Last year I did the front sub frame, urethane bushings, steering coupler, repaint & other good stuff. Then it came time to do the back as well. All bushings, diff seals/hanger mounts, subframe mounts, AND IE camber and toe in adjustments. Well since an alignment needed to be done after the install I went to my full service shop to get the final set up -1 degree of negative camber. Well that’s when the fun began. My shop discovered one, that not only are the adjustment bolts well blocked but the eccentric bolts and washers are not "slotted" on the end that is placed over the side that in bolted on. The other end is welded so the loose eccentric washer is essentially on its own! Neither my BMW guy or the large full service shop I go to knew any real reason to do it that way. So far they are holding and I marked the locations of the set up under the frame to check for movement. I have to say the guy who installed the set up is very knowledgeable and did recommend there over say eccentric bushings, and my other shop is large and fairly reliable. They shop stated that they could not guarantee that the alignment would "hold" due to the way it was designed. The set up is WAY better, but for sure the tech of the kit could be a tad better. It is a MAJOR job no doubt. like 6 hours of shop time. .... remove sub frame, weld, grind, paint, re assemble, etc. So you better need the sub frame out for a good reason.
Oh just as a note I DID call IE after the fact to ask about the reasons for not slotting the bolt and washer.... I can't remember being satisfied with the answer. However, most of my dealings with IE (and I have a lot of their stuff on my car), have been good.