Two vs four subwoofers for music playback

Hello guys,

I currently have a pair of subwoofers for my 2 channel audio system and I enjoy them very much as they make a big difference in sound quality, mostly on body, presence/ambience and 3D image.

I'm thinking about buying an extra pair of subs to emulate a Swarm bass array and smooth out even more the room bass response and get even better dynamics, 3D and presence.

Has anyone had experienced a similar situation?

Has anyone done it?

Can you share your thoughts here? 

Is it worth the expense and the effort of voicing extra subs?