Electrical outlet upgrade worth it?

Mat you *could* realize a nice improvement if your system is capable. Creek integrated - I don't know? It might be up to the task but I can't really say?
My system is pretty hi-res & costly, but even with my very outdated house wiring, adding a $25 Hubbel outlet was worthwhile.
Since then I installed my own dedicated AC line - a world of improvement even with the Hubbel. A 20a industrial Leviton outlet didn't make any improvement over that, but later when I changed to the Leviton-built Wattgate 381 outlet it sounded like a $10000 component upgrade. I make that comparison because, seriously, the Wattgate 381 made about the same improvement level as did replacing my McCormack TLC preamp with a $10000 Accuphase.

Lak, scientists have proven in the lab that bees can't fly!

Bob: If you're not sure about Matty's Creek, I'm sure that you'd find my equipment laughable, although it's set up pretty well and tweaked with lots of cheap, and some not so cheap tweaks. And the difference among the outlets, even in my set-up, is laughably obvious. FWIW, I use an Audiolab 8000A integrated (manufactured in 1986!) with a Cardas Golden Power Cord with the ground floated. My digital front end is an RCA 5223P DVD player with a Harmonic Tech adapter to a 26 guage power cord made out of 47 Labs OTA wire, a Hubbell male plug and Schurter iec. Both the RCA (had an Arcam Alpha 8SE which I sold because the RCA sounded better!) and Audiolab have been damped extensively with industrial floor tile and the RCA is plugged into an Inouye Line conditioner fed by another Cardas Golden PC (actually quite a nice conditioner) which I've changed the outlets in as well. Also have an older Gyrodec and older Elipson (now JM Labs) speakers. So Matty's gear is probably considered to be quite a step up from mine-if I were him, I'd definitely go for it. Ticks me off that I've been listening to my equipment for all these years not really hearing what it can really do. Matty: you can go to the review section here and read a review that I submitted on the cryoed World Power receptacle.

Hdm & Bob, as I’ve said before; it’s a matter of synergy!

Maxgain, who would beleive what honeybees make?

So there you have it Mat. If Blake can realize improvements with his economical setup then certainly you can as well.
BTW I'm not laughing at anyone's equipment here; we all started out from typically humble beginnings, myself included. Much of my very first rig was home-made by myself as a teenager.