Do I need upgraded power cables?

OP, many recommended plugging your amp directly into the wall to not starve the amps draw when using a shared conditioner. Two things:

1. Most are high power amps, tubes and/or mono blocks.
2. Most have installed whole house surge protection, eliminating the need for your conditioner’s surge protection.
I have a lower powered amp (Moon 330A), no whole house surge protection & never play my system loud (sounds great at lower volumes). I have my amp plugged into my 2400 & feel I am loosing nothing while adding protection. YMMV

To Start with, you have some great equipment! The first thing I’d try before I bought anything new, is to plug your amp into a different wall socket (not the same circuit as the Panamax MR4300) and listen to your favorite tunes. After a few days, do you think you hear a difference?  You may or may not. 
A couple of questions. Are you using the factory power cords to the amplifier and the Panamax?

To Start with, you have some great equipment! The first thing I’d try before I bought anything new, is to plug your amp into a different wall socket (not the same circuit as the Panamax MR4300) and listen to your favorite tunes. After a few days, do you think you hear a difference?  You may or may not. 
A couple of questions. Are you using the factory power cords to the amplifier and the Panamax?

I vote for DIY PC, easy, fun and cheap or very moderate cost and I believe they can make a difference but if not still a fun project. I also believe once past a certain point it is not likely to make much of a difference, just cost a lot more and might make a change that fits ones taste more but not really an improvement unless you like and difference in how they sound, if they do so.

I feel the same for all cables and been making my own for a very long time.

If not into DIY there are great low to moderate cost cables as mentioned here already.

Rick

Retired USN tech and very high end sound quality car audio competitor that made all my own cables and used welding cable for the power ones as well as turned down full sponsorships for what I considered snake oil cables.

@wofford 

Salt is to cables, as pepper is to Uranus.