Best speaker cable for Genesis speakers

I am looking to upgrade my speaker cable, and am hoping to get some feedback as to what would be some good candidates to audition. My speakers are the Genesis 4 tower units. Currently I use the Shunyata Orion to run from my Levinson 33H's to the Mid/tweeter towers. This is the cable I am looking to upgrade. I'm not sure that bass response of a particular cable is important, because as I said, this cable is just going from the Levinsons to the mid/tweeter towers, obviously handling the midrange and tweeter ranges only. So, do I only care about the mid to upper performance of a speaker cable, and if so, what is a top candidate to consider? As for the Shunyata Orion....I have no complaints, the system sounds awesome......but I also don't know if there is an opportunity to considerably improve the sound with a cable upgrade, or if it would be a sideways move!!

Regards