Nuprime vs preamp rebuild.


Had previously queried community re value of upgrading dac.  In brief I have an AR SP-3 preamp, Prima Luna HP amp, Magnepan 1.7 speakers.  The dac is from HRT and is (I believe) their original model.  Good quality interconnects and power cord.  Up to this point, have been using Spotify Premium as streaming source.  One respondent recommended getting the SP-3 up to speed.  Last service is long ago, though usage has been light.  The price of a rebuild done by AR is about 3K, all costs considered.  Another respondent advised purchasing a Nuprime 10 which would cover both the preamp and dac issues.  Would very much appreciate any thoughts re these options.  Thanks
jameslsimons
Dear Joe— thanks for your last remarks; they were very helpful.   I phrased my question rather poorly, as an a vs b comparison, not a realistic approach at all.    What I really needed to know was whether those who used this unit were pleased with its performance, and I would say that you have made a strong endorsement.  I am actually in the process of ordering it at this time.  js
I hope I helped and you like the nuprime, it will be in my system for a long time. 

Btw, there is a guy who mods nuprime with their blessing. Most say it's worth it but I haven't tried it yet, focusing on my analog front in for now.