For my 2 cents I'll use an analogy/example. The single easiest and most cost-effective upgrade one can do to gain performance from a vehicle is to get good tires. Literally the rubber meets the road there. For motorcycles, most tires can outperform nearly all riders' capabilities.

With audio its a similar thing. The single biggest and most cost-effective way to upgrade a system is to give it good "traction" with the air where the system meets the air - the speakers. We can chase that last .001% of quality with super pricey capacitors and power supplies that cost as much as a mortgage, etc. Most audiophiles I've read articles from/youtube vids (yes I know... youtube...) agree there. Buy the best speakers you can FIRST and grow into them with your system. Play a super-high quality source through garbage speakers and it wrecks the source material. Play garbage source through great speakers and it reveals the limits of the source.