Proac Response 2 Subwoofer

I am cosidering adding subwoofer(s) to my system to see if that gives me the more full bodied sound I am looking for with this system.

My specific question is whether to buy an older REL Storm/Strata or the newer T-1. They are both available used (Storm/Strata) or closeout (T-1) for about $500 each.

I have not decided whether to add one or two. I am also open to suggestions for another brand, but I have seen great reviews and comments on the REL brand. I don't want to spend more than about $500 for each speaker.

I have searched and read the other postings about subwoofers with my speakers, but I am looking for some advice as much on point as possible.

You can see my system and room in the system link. I am currently using the Quicksilver amp and preamp.

Thanks for your thoughts and suggestions.

Jim Perry