Just to clarify, I did carefully read the OP concerns. I shared my observations because It took me a long time to appreciate the importance of building a strong foundation for a decent sound system. I shared my experiences because I found myself in a similar situation several years ago - at a cross roads on trying to achieve the best sound for the best value for my dollar.
I like most initially looked at investing in the stuff you see, the components. Its not sexy to consider investing substantial money into the hidden unseen parts, like power delivery. But it is those parts that are the foundation of a system. I have seen people waste money buy throwing money at the problem by switching components and speakers in and out of their systems without ever addressing investing in a strong Power delivery foundation.
The point was not to say that too much power is a bad thing, Rather than to point out that the amps design is more than substantial for the speakers he has and is happy with.
He does not necessarily need new amps. However the amps that he has are most likely not performing to their maximum performance. Perhaps - 50% maybe - because they not getting enough power/ electricity to their internal components. If his amps are at not at peak performance neither is his system.
The Power Chords I listed are solely engineered for that purpose. That is all they do. They are specifically designed to insure that maximum power/ electricity is delivery to each component so that the components are operating at their maximum performance. The more Power the greater detail is achieved.
Additionally adding subs does not translate to to blowing out the neighborhood. Easily achieved by volume control. His speakers are rated at 32hz at the low end, to further achieve getting down towards lets say 20Hz with out investing a ton of money he would need to get a sub.
By getting a sub to integrate with the system it would expand the mid to lower mid range increasing the overall sound stage and exposing a level of detail that he is seeking. This is unattainable with just his speakers alone. That sound stage would also have greater spacial separation while simultaneously achieving an overall lower bass response.
This is just another long term cost effective way of looking at achieving or solving the issues the OP is facing.