First off I don't run subs on two channel and I don't have that hi dollar home theatre setup ok but bot truly high end keep that in mind about the following comments.
On the cheap sub in my tv/ home theatre I had some free pos on the sub for the interconnect. I wired a actinote powercord into the powered amp. On that cord I put a connex plug onto it. I got a 10 foot dhlabs subsonic interconnect to run the the sub (biggest difference) I ended up with much deeper bass at a righer volume and tuneful bass not car audio bass. So basically my opinion it is more than worth it to go on the hunt for a powercord. I generally think that the bottom wire in most lines is a big improvement the mid wire is lots better in some areas and not good top to bottom. And the high end of the lines are where I generally look for two channel. But that being said finding the right midrange cord that stresses bass might be your way to get what you want for less. Now on to something I did on my two channel setup or the one pf them. I have a set of levinson 33h amps down there I felt I was bass shy by abunch. Parts connection had a sale on single outlet furutech rhodium receptacle s I bought a pair installed them on each of the dedicated 20 amp circuit s that power the amps. Wow did that ever change the base for they better.lol the slippery slope. I did the other receptacle s in the room one at a time and tried different ones ended up with the top of the line furutech rhodium receptacle s through all but one receptacle. I installed the top of the line furutech rhodium plugs on the captive cords on the amps there again deeper better base. Anyhow that might be a thought for you as well is a receptacle change.