A/b test for like an hour, tape I used on the kc06 didn't like to stay on so I pretty much took it all off and I prefer the stock sound of the kc06. Comparatively the differences were like so
Sub bass: kc06a
Mid bass: kc06a
As a personal preference I like my sound signature a bit bright and clear and the original kc06 sounds fantastic. The kc06a stock had more bass impact and bass was nice and controlled, tape modded kc06 did get a nice bass boost but sounded tad slower and darker. Bass on the modded kc06 sounded bit bloated in comparison to the kc06a. The bass being as powerful as it is on the kc06a bleeds a tad into the mids and treble was a touch hotter than the modded kc06.
Both sound great but I honestly listen to different music on each one stock and use different tips on them regularly but I stuck to the same ones when listening. Ran my dragonfly dac v1.0 to an cable splitter to a/b both without having to keep to keep plugging and uplugging. Also ran the cable splitter with my fiio x5 to how that sound with both for this a/b. Used the medium soft stock silicon ostry tips. (Usually use small heir tips on the kc06)