Downward firing speaker port and domestic issues

Understood. I am mainly concerned about getting flak from the neighbor in the apartment below me should the bass go into their apartment via the floor. 

yes you will get flak. Bass goes everywhere. You cant stop it. Not much you can do about it

I recommend stand mount speakers

Subwoofers and neighbor quiet are opposing concepts.

Better off with sealed on springs.

Perhaps using a pair of Townshend Platforms would help decouple any bass that could migrate to the downstairs apt.

Though, to be honest, I own a floorstander with a bass port (Vandy Treo's), The amount of bass energy exiting is rather low.

Bob