How much do you have to spend?

I have the following. I am pretty happy with the sound, but was contemplating upgrading to KEF Reference 1 Metas which would be another $10k. Wondering whether putting out another $10k would result in significant audible improvements  I probably have about $13k in.  

NAD M33 Integrated Amp

KEF LS50 Metas

2 KEF KC62 subs, with wireless transmitter/receivers

Graham Slee Reference M Phono Preamp

Post-2016 Rega P3, with Ortofon 2MR Bronze

Rega NEO PSU, Groovetracer Reference subplatter, Groovetracer Delrin platter.

Oppo UDP-203 Blu-Ray/SACD player.

I didn't mention used equipment, it's a very different approach.

OP, you have still so far to go before you experience real diminishing returns.

$10k for cables and power cords would be very appropriate in a $100k system. Cables are components and very important ones.

@fritzenheimer that's a sweet and smart system! Especially the KC62s and the NEO!

OP, looking at your system your primary concern should be upgrading to a capable amplifier. Weak link first.

@parkergetdean +100