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
Joe gator and jl35 thank you both very much.  I realize that my question borders on the ridiculous.  I think it is highly unlikely that anyone in this community could meaningfully comment on a rebuilt SP-3 vs. the Nuprime.  At this point cost becomes a real consideration.  To get the rebuild and a high quality dac would run > $4K and the Nuprime would be less than half the amount.  I can afford to go the high cost route, but I am clueless as to whether it might result in better sound.  I very much enjoy and appreciate a good music system, but I am certainly not a cost be damned fanatic.  I think my next move will be to contact the Nuprime distributor in N CA.  And I definitely plan to give Tidal a shot.  Reading the blogs, it is quite interesting how widely opinions vary re Spotify vs Tidal.  About half the people feel that Tidal is significantly better, while the other half feel that Tidal is marginally better at best.  
As is said often, let your ears decide. I think tidal gives 1 month trials. If you decide you like it, take my advice and don't favorite everything you like, build playlists or just favorite the artist and not each individual album. I have found so much amazing music that I'd never have found otherwise and began "favoriting" it all. Tidal runs a lot slower this way, I've not noticed any loss in sound quality but the desk top version is a pain to scroll through. I've noticed no such issues w/ my iPhone though so it may just be my old laptop. 
Thanks for the above.  Given the age of my SP-3, the Nuprime preamp may do just as well, perhaps better, and of course the dac upgrade should be substantial.
I actually went from the HRT to the Halide DAC to the Nuprime. Each jump was very positive. I think as far as the DAC goes you will be impressed. Try to find a dealer that offers a return policy. 
Keep the SP3! It is a TRUE classic and worth some restoration! But don't send it to Audio Research - they will charge way too much! Even in its present state it can compete with today's top preamps! Just changing the power supply caps and adding a set of NOS tubes will be worthwhile! I own an SP6 (1976) - and speak from experience!