New Sub(s) - $500 Budget - Help me Decide

[igotcabada]

Hello,

I'm looking to upgrade the last portion of my system that I feel is currently lacking. I currently have 2 Polk PSW10 subs running, and although they aren't too bad for the money, I really want to get something better.

My budget is firmly set at $500; I would like to keep it under if possible.

Let me know what you think are my best options?

Refer to this room diagram for my layout

Options I was throwing around in my head:

#1. Purchase the best sub I can for my budget. Move one of the PSW10s to the back next to the couch, where the circle is on the diagram. Place new sub up front
#2. Purchase the best sub I can for my budget. Move both of the PSW10s back next to the couch, where the circle is on the diagram and stack them. New sub up front.
#3. Purchase 2 of the best subs I can for my budget. Play around with the 4 subs locations to find whats best. Most likely keeping the 2 new ones up front.

Let me know what ya'll think, I know some of you love giving your opinions!