Yes, the cooling unit affects the flavour IMO. And I do not think I am fooling myself into believing something that is not there because the effect is very noticeable and others have told me the same, in person and in this forum.
After my message, someone commented about using an emptied half of the cooling unit with glass balls as a way to have good cooling while not affecting the flavour much. I have not tried it yet but I want to and see how it feels. You might want to try with that too.
Yeah, the all glass stem with the "glass mesh" to put the herb is great. I have that same one and I am waiting delivery of the new 14mm with "glass mesh" that TinyMight put out recently.
I do think the metal mesh affects the taste a bit and using and all glass path is better, but is a lot less noticeable than with the cooling unit. Only the metal mesh and then all glass gives you a really nice taste honestly.
Even using an all glass path, others have pointed out that reducing the glass path, as in a shorter path from the herb to you, just enough to cool, gives better flavour than a longer path. I have not experimented enough with this because I am still building my glass collection, but you might want to if, like me, you seem to care about the taste. Shape of the glass might influence too.
Also, for the ones thinking that we care too much about taste, I want to point out that different taste means different chemical composition, even if just slightly, and that can potentially affect the high. I understand this is a bit speculative and hard to test, but it makes sense. It is not just being snobbish.
With a cleaner path, that gives "better" flavour, you are getting a more accurate load of what the herb can give. With a more obstructed or metallic paths, with "worse" flavour, you are leaving some compounds or changing the composition, even if slightly. Plus, in general we have evolved to find "better" taste for the things that are better for us. Just like we can taste fresh and rotten food as good and bad tasting, same is likely with the taste of the vapour.
Again, I'll admit it is hard to test. I just really enjoy a good natural flavour while vaping, makes the whole thing a lot more pleasurable and relaxing. I believe that is my brain telling me that's better. But I understand others will not care as much.