Just to add an observation: the REL is a powered sub, so your signal will be going into an amp with a 100k impedance. You will not be attempting to drive the unit's cone woofer, which in turn has an 8 ohm impedance. It should work fine.
REL sub hook up
I have just become the proud owner of a REL Stadium III. I have one quick question. Can I run my main speakers (6ohm Sonus Fabers) off of the SPeaker A connections of my integrated amp, and run the REL high-level connection on the Speaker B posts? This would allow me to switch the sub on/off remotely since the integrated amp remote has speaker selection. I won't run into an impedance problem on the amp, will I? I believe not, but I just want a second opinion.