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. 
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.
if you did nothing else and got the Klipsch Forte III you would have much more heft and weight.  recommended based on hearing them.  
hi I have a pass labs xa25 amp on my jbl 4435 studio monitors they have heft and weight in the bass to 24hz the MIDS and highs are great to do not need a sub woofer bandaid I had jbl l100 cut @45hz I all so have jbl 4425 monitors cut off @45hz all so.for reference bass is the speaker not the room the room can get in the way yes