Speakers can make a difference but it may depend on what is fitted to it , + also how good the head unit is.
I updated an old spacewagon from a cassette radio
to a new kenwood head unit with cd
also has bluetooth and some usb lead.
2 amp channels for driving sound system via external.
Front speakers were expensive Titanium with external tweeters and over E300 when he bought them and to hear them up loud they dont glitch.
Reading up on your unit its not just a radio but can have multiple other things so looks like it wont be getting changed
https://gb-media.vauxhall.co.uk/en-...-new-intellilink-infotainment-and-onstar-adam
need to find the specs on what it comes with.