REL T5i vs SVS SB-1000 in Dual subwoofers setup complimenting Focal Sopra N2

Like alot audio nuts, I never pay too much attention to the bass as most genres I listen to don't call for alot of bass (even ran high efficiency spk with 22w amp before) . But after hearing a set of a true full freq floor stander (Legacy Valor), beside the crazy tech inside, one thing that stood out for me is on low volume, the sound still has alot of body, which I believe I'm missing in my Focal Sopra N2.
From some measurements online, sopra N2 drop around 6-7db from 100-60, and from 40 down it just a rapid rolloff. So I'm trying to see if I can get a pair of small subwoofers to add some body to the low end.
Requirement is rather simple from my simple understanding: seal, no passive radiator, speaker/high level input.

I'm have trouble deciding between the REL T/5i and SB-1000. For new reason, all the new SVS sub do not have speaker level input, which alot of people believe would allow better integration, only the SB-1000 has it. The REL, SHO line is just too much for experimenting, so T/5i is the best candidate.
SVS got better spec, reach lower, beefier amp and all, bigger. REL might have better reputation in 2 ch system, better integration(?!), smaller (its a plus as I live in apartment). They are about similar price.
SVS their ultra live is getting alot of positive reviews.

This is the measurement for the sopra:https://www.soundstage.com/index.php?option=com_content&view=article&id=1445:nrc-measurements-focal-sopra-no2-loudspeakers&catid=77&Itemid=153
 
If there are other suggestion please let me know.