I found some pure silver speaker wire in my storage closet and decided to use them for the subs on my Super 7s. Ordered some new speakOn connectors that had gold plating instead of the steel connectors I had before.
Got everything in and assembled today. Hooked it up and.... wow, the lower mids are MUCH clearer and way better integrated with the mid panels.
It was a bit surprising how much affect it had on the mids, but then again considering how high the subs play up to, it actually makes sense.
Anyway, lesson learned - the cabling on the subs matters. If you have generic wire on your subs, try out something better, you might be surprised!