Hello. I currently have a 5.1 setup with all polk inwalls, minus the center. I just purchased a second exact sub psw125, and was wondering before I open it if this would improve my ht sound. I use an onkyo 809 receiver.
It should provide a bit more output overall and a bit more headroom for each sub, and it should smooth out the response. Whether it does these things sufficiently in your HT space to offset the additional cost to you is, ultimately, your call.