Will I benefit from upgrading REL subwoofer pair

Hi Audiogoners,

I am only about 4 years into my quality audio journey. As a result, I bought elements of my set up at different times in the journey. Right now, I am using a Lumin T2 feeding a Hegel H390 amp which animate Focal Kanta 2 speakers. All cables upgraded. I also have duel REL Tx/7 subwoofers - which I thought were great until I upgraded my ethernet switch.

This small change lowered the noise floor in my largish (25' x 20') room and suddenly the subs started to sound a little flabby. So I upgraded their hi-level connection to the REL Bassline Blue cables. Much much better. 

But it led me to wonder if I should sell the duel Tx/7 subs and get a single REL S510 (and eventually 2 of the S510s). 

I *think* the speed of the Tx/7 s is sufficient but they may not be a match for the Kanta 2 speakers.... 

Does anyone have any experience with these components? Or advice?

Thanks Nadine