Quality of outlet not directly powering equipment important?

My new room that I have dedicated to music Has 5 outlets. They are all daisy chained around the perimeter of the room. They share nothing else on the circuit.  From left to right of the room, the power goes from 1-5.   The system is powered by outlet 4, which is an SR black.  The house was built with very poor outlets, the kind that literaly bite down on the wire using a hole for insertion and a quick release tab, not even screw down terminals.  

Upon seeing these POS outlets, which are in my "chain", I replaced outlets 1-3 with my collection of audiophile grade outlets. 1, with a wattgate 381 silver cryo, 2, with a teslaplex SE, And  3 with a furutech gtx-d (r).  I did this to at least have high quality links for the Romex to feed the SR BLACK (4).   I would assume that even with this "mix" of outlets in the chain, they must certainly be better than the absolute garbage outlets that were links in my electrical circuit.  I would imagine less voltage drop at the very least.
 
Now, outlet 5 remains a contractor POS outlet. Its technically past the system, but being that this AC, and not DC, wouldn't it technically also be part of the AC chain feeding the stereo? Would it behoove me to change that one out even though it's past the stereo and not before the stereo?