upgrades

Hello What HI-FI community, I'm new here and this is my first post. I'm looking for some advice / recommendations for upgrading my system. - Source: Cambridge Audio MXN10 streamer (streaming lossless audio from apple music) - Source cables: Gold plated RCA - Amplifier: Marantz PM 6003 -...

I have a vintage late 1980's Rega Planner 3. All serviced and a new RP303 arm, 24 v power supply, upgraded belt and rewired arm. New AT 540ML cartridge. I am very happy with it and now curious about upgrades. (Or in fact whether to stop where I am and enjoy it...) I saw the Delrin aluminium...