I know i shouldn’t mess with what already sounds good.But i do like trying to get that little bit extra out of my system if possible,soundwise,not speed everything is running super fast with Roon
What do you think i could improve on this set up ?
NUC 7i5 ,connected 4TB HD-Flacs and 24 bit hi res files.
Networked to SMS 200,powered by Sbooster 12v Ultra addon.
USB to Cambridge 851N Network player.
I have no album art on the CA851,it doesn’t support Roon ,therefore using the SMS200 so i can play my HI res Files.
Improvements would depend on what you perceive to be wrong or lacking in your current setup? You could spend loads of money making changes, but if you enjoy listening to music on your current setup, why bother?!
Cos i like tinkering
No mention of amp and speakers. I’d start there or leave alone if you’re happy with the sound.
If you like tinkering buy an Arduino and build a laser data link. 
I’d not bother doing anything with the computing end of things - unless you are already having glitches due to lack of computing power (highly unlikely with that setup unless doing heavy DSP to a number of zones) then tinkering isnt going to yield any noticeable difference.
As Martin said, the biggest difference is likely to be achieved on the analogue end.