REL Subwoofer: Speakon or RCA?

So, I'm currently connecting my Rogue Cronus Magnum amp to my REL Subwoofer using L/R RCA Cables. I'm leaving the amp via its variable output L/R RCA connection to the REL subwoofer L/R RCA inputs. I'm satisfied with the results. But now am wondering if, practically, I would hear an improvement (if so where? how?) if I switched to the Speakon cable for connection type. What do you think?
I'm a REL dealer. Speakon is way better because the amp in the REL will emulate the character of the amp so the blending and seamlessness is much better.  It will sound like the amp in the REL is a Rogue.
I've  used Speakon stuff for years in pro audio so when I acquired a couple of RELs over the years I adopted their philosophy of the high level input for the reasons mentioned in audiobunker's post, and because I like Speakon Neutrik plugs...I make cables for the RELs from Canare Star Quad, AQ spades, and Speakon plugs...shrink tubes galore. I have to "stack" the spades on the posts of my amp, but that works fine as the main speaker's cables are bananas. Neutrik...made in Lichtenstein...
Speakon is the way to go...BUT be very careful how you do the set up and look at the videos above. Speakon is a balanced connection and that needs to be considered when hooking up to a balanced amp. 
There are other variables depending on your amp type, but the videos do a good job of covering them.
Long runs of RCA single ended cables aren't a good idea, but the 100,000 ohm REL "signal stealing" High Level input system doesn't seem to care how long the amp driven cable is. Plus it's easy to build them yourself.