Getting 2 subs

I think you are flailing for a solution right now and we need to get you back to simple, and straightforward, though that may take some effort on your part.

What are your main speakers? How have you connected them? Is there a high pass filter in place? Have you measured your current state? How large is your room?

How about speaker placement? Try the AM Acoustics room mode simulator first. It will help you see where the lowest modes are. Keep all your speakers and your listening room out of them if possible.

https://amcoustics.com/tools/amroc

With your large floor standers a pair of subs should be an easy set up...when I set up 2 subs with large floor standers, everyone I talked to, said to get identical subs …

Guess I missed the D3's right there.... for some reason I thought those were subs too.  :D

Is your room overly reflective?  This can create excess mid-treble energy, and overwhelm the bass.

I use to great satisfaction 3 different SVS subs in my main room. A SB4000, a SB3000 and a PC2000 Ultra. The 4000 crosses at 60hz, the 3000 at 80hz and the 2000 at 100hz. After playing with the gain for some time it is now dialed in seamlessly. You never hear any indication of a subwoofer and yet there is a dynamic that is hard to explain. The interplay of the subs does magic to my bottom end and the music is captivating. 

The 3 different SVS subs is something I considered, now that I know it works, that’s probably what I’m gonna do,  only gonna get 2 subs, which should I get ? The sb 4000 and the 3000 or the 4000 with the 2000?