So great questions! I will start by saying “everything makes a difference or nothing makes a difference.”
The question for you is, it worth the money in the end? Again, already stated above, you will have to decide and make sure you have a return option.
So for me in my system the upgrade from the very same Panamax to a Audioquest Niagra 1200 was not subtle! you are correct the Panamax is basically surge protection, no noise filtering or suppression. After that I proceeded to change out the power cable to the Niagra, then to the amp. The next would be your digital power and or pre amp. A great way to do this is using the lending library at The Cable Company! Call Steve, tell him what you have and pay to loan them out for two weeks. If you can’t tell any difference, return them and you had a nice forced listening session, if you did hear a difference you buy new or demo and apply your loan fee toward the purchase. A win win for very little money.
I will leave you with this, sea salt tastes different than mineral salt, and pink salt tastes different still! They are all salt!