moving from house to an apartment.. goodbye 802D's

I have these on my sub woofers:
The SVS SoundPath Subwoofer Isolation System They provide decoupling and isolate speakers and subwoofers from the floor.
They really seem to work and are very well made. They come with different threaded stud sizes so they should just screw into the bottom of your speakers

I wouldn't do anything until you meet the neighbors.  Because you don't have a problem yet.

I had one neighbor a retired school teacher that encouraged me to be 'loud' because she appreciated having younger folks around. 

I also have had neighbors that were pilots (never home) and lived above the model (no one there beyond the business day).

I'd agree with the advice here to meet the neighbors and assess the specific situation first.
If noise is going to be a problem, switching out your B&Ws for a subwoofer won't save you! Unless the point is that a subwoofer can be turned off. 

The issue is that bass travels easily through floors and walls, whereas higher frequency sound is more easily arrested. My downstairs neighbor has an inexpensive subwoofer, and I hear the basslines through my pillow when he puts on his "morning music" at 6 am.

Jeez!  Just don't turn them up!

Thanks audio friends for all  of  the help.  I'm keeping'm!!