If your only concern is will the M100 give you a measurable increase in the lower spectrum, then you need not worry. I ran my LFRs alone for quite some time and only recently put in some EP500s. For the most part the increase in sound isn't that noticeable except in music that actually gets down sub 40hz that you hear any improvement from subs being on.

You do with some classical pieces and a bit more warmer glow to Holly Cole.

Anthem: AVM60, Fosi DAC-Q5
Axiom: ADA1500, LFR1100 Actiive, QS8, EP500, M3, M3comp, M5