Lumin upgrade - built-in or separate DAC?

I've got the rest of my system sounding nice enough and since I mostly use my NAS or stream Tidal nowadays, I want to upgrade my digital front end from a Mytek Brooklyn DAC+ and Bluesound Node 2 (used as a streamer only) to something better. My local audio store says I will notice a huge improvement if I upgrade the streamer only and continue to use my current (Mytek) DAC. He suggested going with the Lumin U1 mini and a Sbooster linear power supply. I am already using a Sbooster for my DAC and have a Shunyata power cord on my Node 2. 

Does anyone have experience going from separate streamer and separate DAC to a combined unit? 
My thought is that if I have an "all in one" streamer/DAC, I can get rid of having to use 2 units that need cables to connect and less wires/connection in the signal path and ultimately better sound.

Here's what I'm considering (in no particular order):

*Save $ for about a year to buy the Lumin X1
*Buy a used Lumin S1
*Buy the full size Lumin U1 and use my current Mytek DAC
*Buy the Lumin U1 mini, another Sbooster and use my current Mytek DAC.

The rest of the system is pretty good (in my humble opinion). I have all the other pre-requisites such as good speakers, amp, speaker cables, dedicated lines with 10ga wiring, digital cable, interconnects. The other items I'm working on is room treatment and making stands to get the speakers right at ear level.