When you add subs, make sure you add a pair. Although deep bass is not directional, your right and left channels will still produce different bass. Put the subs in the corner and spend the rest of your time tweaking. You may also want to consider passive bass filters, depending upon your sub. I'm not familiar with ML subs or if there might be synergies with your CLS, which there apparently is per previous posts.
All of new equipment aside, you may want to consider your point of diminishing returns. Put another way, at what point are improvements lost upon you? If you're a concert musician, you probably CAN hear every nuance John Atkinson claims to hear. If you're a combat veteran in the artillery, you may not hear the difference between Bose and well placed electrostats. Are you chasing something that you have to convince yourself is true? This is the stuff of audio cables. Here's my story:
I'm a fan of A/B testing, though it's not necessarily double blind. I decided to upgrade cables. I had 16ga solid core and Transparent MusicWave. Frankly, I couldn't hear the difference after testing. At a certain point, I realized that I was trying really hard to attributing things to the MusicWave that probably weren't there. I was trying way too hard. Then, I decided to make cables from Canare stock. Did spade terminations on them and plugged them in. I COULD hear the difference. It was a difference I liked. For more cable, I paid less for the Canare than the Transparent.
I also did an A/B test on my amps. I started off with an old 80s Denon receiver. Then, I upgraded to an Adcom with Linn Wakonda preamp. A nice difference, but probably not worth it. When I replaced the Adcom with the Aragon, the system came to life! I had bass for once! Amazing! And then I added a Vandersteen sub. Again, a noticeable difference, but not as big a jump as I went from Adcom to Aragon.
What I'm driving at is that this hobby, like everything else in life, is the exploration of what makes you smile and happy. Once you get there, enjoy! Don't chase an auditory phantom, unless chasing that phantom is what makes you smile and happy - and if the chase is your happy, then maximize the happiness of that chase!
For me, my Aerius i's are well matched with the Linn Wakonda and Aragon. I like exploring, so I picked up a pair of B&W 801 Matrix 2. BJC cables with a spare Aragon 4004 Mk II amp. Shopping for a preamp, but leaning towards an Audible Illusion 3A or 3B. Yes, I realize I'm intentionally coloring my new system with tubes. After playing with ss for so long, I'm curious about tubes. So, why the hell not. It's my happy and no one else's.
You've got a rockin' system. Find your happy!