It may affect how ZO/SmartVektor sounds though which it does to my ears.
Well I must say CKS77 smoothens out slightly by burn-in. The upper-mid peakiness is a bit better after the over-night burn-in but still very much there (used bassy Hardstyle coupled with ZO2.1 for some serious bass response to get the drivers a good work out), currently listening with EQ disabled and it sounds quite listenable with occasional harshness/shoutiness popping up here and there. Using the tip position further away surely helps too to flatten out the sound but too shame the overall sound signature is a bit too distant then (especially the distance to the mids; the vocalists, instruments etc in that case). The bass is very powerful when I'm listening atm with ZO2.1 even at a few levels below what I typically use with Q40, maybe lvl3-4 vs lvl7 or so. However I still miss the "bass-massage" feeling a headphone can give which IEMs doesn't (quantity wise this is roughly similar but it obviously doesn't feel the same as a fullsize headphone).
It sounds best paired with ZO2.1 but it also has more hissing than with ZO2.3. Does any1 know of any impedance-cables I could try, the IEM is also SCARINGLY loud with ZO2.1. With highest vol setting on ZO2.1, I have to use 6% volume in windows.... :O
It's clear at this point I won't become an IEM-guy but I don't regret the purchase though as it's worth having an IEM that comes very close to my preferred sound.