Hi @andychampionsound
First of all it really depends how you use the S30 in your setup. In my experience S30 is best used only as a player. It just does not have a lot of power being a server and player (& DAC?) at the same time. So the more you can separate these functions by putting a separate streamer before - and a DAC after the S30, the better the sound will be. Playing your music from a S30 internal SSD (Samsung PM893 recommended) vs streaming will also sound better.
A superior external DAC (usb in) will improve the sound without spending too much. This will allow you to tune the sound to your liking compared to the build in DAC. More analytical vs. more warm or more analogue for example. Your ears will tell you so make sure you can try before you buy.
If ever you choose a 12v DAC (ex. Chord2Qute) an extra and not to underestimate uptick in sound quality is also to be expected if you power it with (a good dc cable and) the excellent S60 power supply (12v) since it has two 12v outputs.