Triode User
Member of the Trade: WAVE High Fidelity
As you have already LPS-1, i advise you to try IsoRegen from UpTone Audio as it costs 325$ which IMHO it is mandatory tweak despite Dave is immune to USB cable and it is well galvanized but what i got from IsoRegen is other worldly.
You can find a lot of appreciation from audiophiles in CA forum to IsoRegen.
There are other tweaks from SoTM but it will cost an additional thousand dollars.
AFAIK from @Rob Watts, he didn't recommend an external clock but may be he has another opinion for these tweaks, i don't know but this is what i got and indeed i like it.
This is a hobby and not a competition so of course we can all do what we want as long as it makes us happy. But you are right that Rob Watts does not share the enthusiasm for upstream tweaks to Dave. Just as with exotic cables, I continue not to spend on these sort of tweaks and will put the money saved into the kitty for the next main box upgrade eg amp, dac or whatever. The proverbial YMMV applies and as long as your music makes you smile then I support it.