Rel sub bass units integrate really well with many different speakers. I have a Storm 3 and love it. They MUST be meticulously dialed in, but those efforts will be rewarded quite nicely. Quadophile has written an excellent and detailed review of the Rel Acoustics Strata Mk III on Audiogon:
Rel Strata Mk III Review by Quadophile
Rel Strata Mk III Review by Quadophile