floor standing speaker for shared wall? (front ported or enclosed tower options)

Sorry- what are columns?

You would think in a townhouse, the walls and floors would be better than most.  Are your speakers decoupled? That will cause rumble in a neighboring room.

If the rooms share common flooring, on stem wall foundations, with common floor joist,  they transfer a lot of harmonics. 

Decoupling the speakers is probably the best and least expensive way to help you and your neighbor.

Could probably add some nice Columns and add better bass. 
The neighbors won't notice as much, but your experience will be greatly enhanced.. Me and my columns.. I love um'

Just a thought..

Regards

Oops- looking to stay below 1k$.