I think you'll like Alpha Core MI 2 if you want to clean up the midrange and still get a bang at both frequency extremes. What Polk's are you using, I used to use the srs sda 2.3tl's, in fact I still have them but not in any system.
Bryston 14BST and Polk SDA SRS Speaker Cable?
I'm currently running some thick Monster Cable (model number escapes me) speaker cable and would like to upgrade to a bi wire set up for this rig. I'm pushing a lot of power and like to listen to rock and blues music on the loud side. I'd like a cleaner (less muddy?) midrange (if this is possible with a cable adjustment). Top and bottom end are fine. Current research has me leaning to bi wire Kimber 8 TCs or an Alpha Core M1 bi wire. Used Cable.com recommended a new "Wireworld Atlantis III+ Internal Biwire" as the "perfect" match. However, I'm a tad skeptical, as this cable is the one currently on a special purchase on their sister company, "The Cable Company". Any suggestions in the $500 range?