Disclaimer: I don't have any of these (yet), so who am I to say, but I'm going to give my expert opinion anyhow...
Since I've been looking into all of these options for my new LC, I have been reading with interest all of the opinions and real-world experiences and such. And
@Taco2Cruiser , I appreciate your experience, especially the info about the easy adjustability of the "race" type shock Icons vs. the OME's, etc. I have also paid attention to what others have said about durability, ride quality, problems, pros/cons of the different makes.
I don't think that the "race" shocks should have any stickiness, loud valve operation, or any other noise-making bang/pop/thud/clunk/hammer/tap/rattle, or any noise other than the sound of fluid flow just because they are "race" shocks. I don't think any of the manufacturers or their engineers would think that is acceptable in any way. And from what I have seen on this forum and others, and youtube videos, it reasonably appears that people are having clunking and rattling noises coming from their suspensions after installing these products.
The key information in this is that most of these people are DIY, or are going to their local "off-road" garage, and who knows what level of experience, knowledge or expertise they are finding there, if any. I have serious doubts that most of these parts-changers have any real idea what they are doing, what the nuances of design and engineering application are, or what problems can develop from lack of attention to detail and quality control.
The other key information is that these noises developed after making the suspension modifications. So the suspect is obviously what was changed at that time.
So now for the expert opinion: There is something loose somewhere, and most probably it is the shock eyelet/bolt/bushing mounting hardware. These new lifted off-road suspension systems that guys are installing seem to be working fine in most use, even off-road, so the idea that there is some faulty shock valve or something is unlikely. And the fact that the noise is noticable on relatively smooth highways, when just hitting normal cracks in the streets is very informative. This means that it is a very small tolerance part that has just enough free slip to move around under light motion, maybe only a millimeter. The big whoops and drops off-road are making noise once in each direction, but on-road it's a rattle - on every bump.
I would suggest to these guys that they double-check the interference fit and size difference at the ends of the shock at the eyelets, to make sure the mounting bolt and eyelet bushing are snug fit. Any gap here will move. Same goes for the UCA and LCA mounting bushings/cams/bolts. All of this stuff should be almost interference fit, not 0.5 mm and maybe not even 0.1 mm - or there will be noise. You can't put a 14mm bolt in a 15mm bushing and expect that tightening the bolt will stop it from moving - it won't.
As usual - just my $0.02.