Best Music Streaming Hardware Options


I’m in the process of building my system around my Apogee Acoustics Duetta Signature Series II electrostatic speakers. I just bought a BAT VK-600 amp w/ BAT pack and will soon purchase a BAT preamp. Currently, I stream Spotify at their highest 320 kbps compressed mp3 format, but I know I’ll need to get to at least CD/SACD quality. Apogees are very unforgiving towards source material that is lacking. Looking for recommendations from fellow audiophiles in two areas...
1. What is the best way for me to tackle Hi-Res streaming (Tidal, etc) from my iPhone over WIFI/Bluetooth (not sure if this is a good option compared to a player that does the streaming), cd/maybe SACD playback/upconvert? An example I’m thinking of is an all-in-one player such as Sony produces (at least as of a year ago was around $2k new).
2. Any recommendations for a tight budget are ideal. I would be looking for a preowned unit. I realize this portion will probably end up being the weakest link in the chain since my budget is tight, but trying to minimize impact as much as possible while being able to continue my obsession of discovering new music constantly like I do currently with Spotify.
Thanks in advance!
parker65310
Nice catch. You are right on them being planar, not electrostatic. I say that knowing I am incorrect when I stop to think about it. My dad has had these speakers since he bought them in the '80s. They are mint and have always been my favorite sounding. Love the wall of sound effect. Put out a lot of energy. I debate if he upgraded when he went to Martin-Logan electrostatics. Either way, I came out a winner in my mind :). 
I appreciate the recommendations. I will check them out. The  bluesound node 2 loomisjohnson recommends looks promising as well from what I've read about it so far.

+2 for Bluesound.
I use a Node (1) and an Ayre Codex as the DAC. The node provides wireless connectivity through out the house and the Ayre provides upgraded sound quality at a great price point.
B
A Raspberry Pi3 is the cheapest but in my opinion it isn't the best if you're looking to stream from your phone. There is a certain input lag from button to music playing, especially if using Airplay that drove me nuts.

I would seriously consider something from Auralic, Aries Mini would be a good budget friendly option.
Hard to say what's "best" these days with streaming, since things are evolving pretty fast.  I've taken what I believe to be moderate approach, tech-wise, with the understanding that a few years from now I'll be making another change to digital.  My Sony HAP-Z1ES streamer/DAC (integrated unit) works very conveniently with Spotify. Retail price is about $2K, but it's available new for less here and there. It allows use of the excellent Sony App with tablet/phone.  I especially like that if I do a few clicks in just the *Spotify* app, the Sony can be turned on remotely without even using the Sony app.  Very nice for streaming.  But the Sony App is great too.  The HQP-Z1ES does not currently (at least not YET) allow Tidal streaming, however.  Nor does it (YET) allow MQA, for what that's worth. Firmware updates in future may change some of the latter statements.

With the Sony HAP-Z1ES, there's also a 1 TB (expandable) hard drive on board that allows storage of ripped CDs and other digital music.

+3 on the Bluesound Node2. If you are on a REALLY tight budget , the previous generation, the Node N100, is available on Amazon at $300 and for less 2nd hand. It will still sound really good on the Tidal MQA files. If your budget allows it, another (significant) step up would be a Lumin D1 streamer which may be available for around $1K second hand, if one can be found. The Lumin will upsample and upgrade the sound on non-MQA files as well.