I do happen to like the 11 better than the 18. 18 is too warm for me and I have gotten to like the UE11.  I don't hear it like these measurements (but after 9kHz the measurements are unreliable and we may not hear that peak)?
 
After having and spending time with all of the demos, there are 3 options that I am still considering as a second pair...
UE4:       Best value & clear sound.  "Baby UERM".   I can work out with them and not feel guilty.  Clear shells only.
UE11:     Some U-shape but the bass/low bass seem tight & more linear with proper amping.  Fun + a good compliment to the UERM.
UE PRM:  Adding treble in my left ear makes for a more coherent sound and better balance. 
 
I need to try some amping before the tuning box to see if that helps the PRM demo bass control.  (The UE11 also lose some bass control without good amping.)