I'm glad that my impressions of the awesome UE18 PRO somewhat mirror yours, as I was only able to demo them (and you own them outright). I feel that the universal UE18 PRO had great separation and presentation, but the quality and intensity of its bass was still lacking compared to my SE846 with SCS. I'm sure the custom version would have a little better bass. Overall it was my favorite IEM of the head-fi meet a couple of weeks ago. Also, the modded black filters of the SE846 (almost like the white filters) opened up the treble/higher frequencies that the blue and black filters automatically veil. What color SCS do you have? Any pictures?
I have the pink color. Mine is the "modified" sleeve. Shorter bore.