Need more heft

In the market for floor standing full range speakers. Would appreciate recommendations up to $4K. 
Current rig:

VPI Scout TT
Lyra Delos MCPass Labs XP12 pre
Pass Labs XP17 phono pre
Pass Labs XA25 ampZU Audio Soul MK 2 Speakers
ZU cable
Love the mid range and immediacy of the speakers but they have no heft or bottom end/bass extension which is what I am seeking. Not interested in adding a sub. 
For reference, I’ve researched ZU Omen Def MK2, Kef, Focal, Klipsch Forte 3 and Heresy 4, JBL L100 and Golden Ear. 
Appreciate your feedback in advance. 
My weakest link, due to large room is my Emerald Physics KCIIs

But last night I decided to replace an $800 boutique power cord with a WireWorld Electra 7 MSRP $240 to my Core Power 1800 which plugs into a 20 amp dedicated line. This completes my Electra 7 cords powering my system

I am shocked what this one inexpensive change made across the board, especially noticed in the bass, which came alive

Check out the Golden Ear speaker line. They offer great performance at an affordable price range, including powered bass.
Would the XA25 work with Vandersteen model 3?
Doubt it.

I am struggling to think of a speaker I have heard that has a signature like the OP’s speakers, and will give deep bass with 25 watts.  I know it is not what the OP wants but his / her best use of the budget is probably a Vandersteen Sub 3 or a Rel sub. 
Have you tried playing with the floor gap on the Souls?  Try raising the gap to somewhere between 1/2" to 5/8".  That should give you fuller (but looser) bass, but with your Pass electronics that won't be much of a penalty.