upgrade question regarding DAC and streamer

Wow, that is a really challenging question... complex. 

I have owned Sonus Faber Olympica for many years, I upgraded to Sonus Faber Amati Traditional a few years ago. 

After some thought. I would recommend spending some time planning where you want  your system to go, then slowly replacing one component at a time. 

Imaging is the result of your whole system. The heart of your system is the preamp. Your streamer isn’t too bad... so it really does not make sense to replace that until you have the permanent "core system sound". That would come from your preamp, amp, and speakers. Then you would upgrade your front end. 

Your speakers can support the sound you want... and be a bit forgiving and musical. Good that you chose those first. 

The first thing you want to do is to identify your target sound. One way of looking at different sound types...1)  highly detailed / analytical / a bit dry... but holographic... Burmeister, Luxman, on this side, 2) Middle of the road, MacIntosh... warm, bassy, but lacking in detail (important for imaging), and 3) highly musical, natural sounding, for instance, Audio Rearch, Conrad Johnson. 

Outstanding imaging can easily come from any, but the first and last are the most easily achieved. It is critical at your stage to decide where you want to go. Be very careful with treble... excessive treble gives the impression of great detail and imaging... but can be fatiguing or lack musicality... by having an attenuated midrange. Midrange is the key to the emotional connection with music. 

I recommend a lot of auditioning to determine what camp your tastes are in. The first component would be recommend searching for would be a great preamp... consider used to get as high up the audio chain you can get. I favor Audio Research and Conrad Johnson. Then amp... then finally DAC and then streamer. 

If I was doing this, it could easily take a couple years to slowly choose and upgrade all the components. But when done, you will have an incredible system. 

In between auditioning (consider travel)  different systems, try mix in some real acoustic music... symphony, small jazz group, and/ or individual instruments. Calibrating yourself with real music will be really advantageous in the long run. 

If you are interested, my systems are shown under my userID. 

Since you have a good relationship with your dealer I’d think they would let you demo some streamers/DACs in your system and then you’ll know.  Personally I’m not a fan of combo units and would keep these things separate, but that’s me.  Beyond that, I agree with @ghdprentice that for imaging/soundstage I’d look to the preamp and then the amp first.  Your streamer with the LPS is on the level of the Innuos Zen, which is pretty solid and would again point me toward the pre/amp first.  That’s not to say a better streamer and DAC won’t make significant improvements because they certainly can, but again a demo would go a long way toward seeing if that’s the right thing to address given what you’re looking for.  I’ve not been a McIntosh fan in the past because I found their sound overly warm/lush and veiled in the treble/upper mids although they seem to have shifted their sound profile toward more detail include the treble/upper mids.  Still, if I’m looking for a more expanded 3D soundstage McIntosh is not where I’d go, and something like ARC and some others would offer more improvement there I’d think.  One thing I’d very strongly consider is a tube preamp if going to a tube amp is a bit too much.  Just some thoughts FWIW, and best of luck.

If you have only one source you may want to consider 

1. Best dac you can afford that has excellent preamp built in

2. A very good stereo amplifier

IMO your MA8950 is almost as much of a bottleneck as its built in DAC if you are looking for greater precision and focus. MSB has option for streamer and has a decent built in preamp from what I read. It should be in a right direction 

Wonderfully complex question and you’re sure to receive lots of opinions. I recently upgraded from a McIntosh C52 preamp which uses the same DAC as you are currently using. You are wise to consider upgrading because I know now that the Mac DAC was very limiting. My path led me to a Roon Nucleus+ with upgraded power supply and network filter, quality USB feeding an Allnic D-10000 DAC. Well, at the upper end of your budget, this solution seems like endgame. The tube DAC is OTL (read about it if you are unfamiliar). It produces an analog-like sound that even discerning vinyl only friends find impressive. It is forgiving with poorly recorded 90s digital music yet brings the most out of well recorded music. I absolutely love it.

I would follow all the advice you are getting with these guys, I have been going round and round for a couple weeks on a streamer that fits my listening tastes and what’s fits in my system. All the advice from this forum made me read, audition, talk a lot  with the wife, friends and finally decided on the Nagra streamer. It’s easy to use, no fluff and stuff, I don’t need art work looking back at me from a distance, I have my iPad, a Ethernet cable, a RCA cable and a electric plug in and you are done. It’s small, high quality, easy to integrate into your system and you are not paying for a dac you don’t need, in my case. All the streaming services are built in..