Matching subwoofer

These questions come up so often that I wrote a blog post about it:
https://speakermakersjourney.blogspot.com/2020/04/how-to-not-buy-subwoofer.html

Best,
Erik

you dont need a subwoofer. 

In my opinion, Vandersteen has the best way to integrate subwoofers into a system.
The Debra system is often mentioned, and I know Atmasphere considers it quite good (and I respect his opinion),
But, from my personal experience, I know Vandy subs that are 30 years old, still perform as they should. Though they require the use of an external crossover, they really fade into a room when properly configured.
I am moving to the new Sub 3's and expect the equalization ability to be as good as the 4 sub method espoused by the Debra.
If I had:
The Time
The Money
The Room, 
I would try both systems.
But, I don't.😜
Bob

The best way to integrate subwoofers into a system is to bus them to a neighborhood with no subwoofers.  

My subs are less than two years old. They fade right into the room. With the lava lamp on you can barely even see them.

Have you considered an Omega sub to mate with your speakers? I use a DeepHemp 8 with my Super 3i's. Perfect match. It added that foundation I was looking for as well. Louis makes great speakers, including subs.