Here’s a version from Janus’s file using my template (mainly because I was curious): VSL VI running in VEPro - 20 year old samples - Ist. Vlns. are CSS
I’m using MIR and note length conditions in the EM’s. I just got rid of a couple of staccato marks because they triggered something which sounded too short, but apart from that, no other tweaking. Fabfilter Limiter, small amount of SSL Compressor and a touch of extra reverb from Altiverb - These plugins are always on the Dorico stereo output. I started out in 1986 with a Yamaha FB-01! I remember all the hardware mentioned here, including the Proteus which was considered pretty good at the time. My pride and joy for many years was the Kurzweil - K2500R. I started with VSL and the gigasampler when they first started in 2000 and they changed everything! The VI libraries have always worked well for me.
Very nice! But please correct bars 26-27 as I mentioned earlier… Or is it just me? 
Really great.
@Grainger2001
at last – one that actually sounds like music! I’ve replaced my VSL VI stuff with Synchron but that’s more for convenience than any actual improvement. Still, I tend to prefer CSS for full orchestra, using VSL more for chamber works (although the Mozart is a bit of a halfway house, arguably)
I’ve uploaded an edit to correct the error.
I really like the piano passages, but hate the forte (where it suddenly sounds overblown and artificial)
To some extent I agree – the horns are much too loud and sound pretty unpleasant (I mean the second entry later on)-- that’s the only thing that really annoys me a bit though the articulation could be a bit cleaner. There is more weight of sound than with many modern performances but that is not in itself a problem - it’s more a matter of taste.
this is what happens with Cinematic Studio running under NPPE (using the Janus score).
VSL really shines! A pleasant surprise has been to hear how well comparatively the Iconica Sketch has fared -to my ears- in all this.
None of these are actually usable examples. The reason is: Mozart should be played with baroque instruments in 432 Hz. Baroque strings sound totally different. If you have this music in your head and have often conducted the piece, then all VST instruments sound bad. It would have been better to use something from the Romantic period or the 20th century; Bethoven, Haydn or French composers like Ravel or Debussy. I think that you can then better judge the sound of these different setups. Thanks anyway… that’s good too
I had one of those!
Feel free to upload your own test score for comparison.
There are some other examples on the forum - Mahler, Stravinsky and Wagner. that might interest you.
ok. lets call them Classical instruments, same for the woodwinds:
In your opinion which many disagree with. How do we know that Mozart wouldn’t have preferred modern instruments if he had lived to hear them? We simply can’t tell.
If he’d lived to hear modern instruments, he wouldn’t have been Mozart. That’s hardly a compelling argument. The sound ideal of modern instruments, with equality throughout the registers, is quite different from that of the classical and baroque instruments, with considerable register differentiation. I’d kind of hoped we’d gotten away from the idea that everything modern is an improvement on what was made in the past.
the argument is meant to be if modern instruments had been available in Mozart’s time. Obviously if Mozart had been writing nowadays he would have written quite differently – I fully accept that point! And although on the whole I tend to prefer modern instruments, I’m not at all dogmatic about it. There are certainly exceptions (and I’ve enjoyed using Baroque virtual instruments in a couple of my own works). My problem is the dogmatists who can’t accept modern instruments at all and don’t really see why different approaches cannot be embraced.
Generalisations should never become dogma.
The performance of Mozart’s works in Rome, Vienna, Paris, and London would all have been performed at different pitches during his lifetime.
Indeed, in the 1780s, “Wiener-ton” was pretty close to 440.
I recommend “The Story of A” by Bruce Haynes, an excellent book about the history of pitch.
The name Wendy Carlos comes to mind here. 
The “classical instruments” were very modern at Mozart’s time, indeed. Most good string instruments had started a process, where the violinmakers changing / modernising the instruments (stronger bass bar, tilting the neck slightly etc.). But also wind instruments were in constant development.
Example Clarinet: https://youtu.be/D3NCGSvKHCQ?si=GCm9qoddM8r-GDyn
Example Horn: https://youtu.be/PLHC8I8RwMg?si=AnB4GS49ZFluLvyZ
We do know that Mozart had no choice but to write for instruments that were available at the time in Salzburg and Prague, otherwise his symphonies couldn’t be played. According to Adam Carse, this changed in 1777-8 after Mozart heard the Mannheim orchestra for the first time and learned about orchestral crescendo/diminuendo, ensemble playing, clarinets, etc. The Paris symphony was written after that and insisted on a new setup that became the established “classical” orchestra. It was also a breakthrough in orchestration technique that Haydn himself copied.
This is considered a watershed event that also contributed to the need for more capable performers and playing techniques - and Carse specifically mentions Mozart’s Es-dur symphony as an example of rather daring writing for clarinets. Perhaps it’s not unreasonable to believe that Mozart would have wanted to use the most modern instrument versions available as long as they enabled better technique and produced superior sound (something that didn’t happen for horns for a long time). Carse even says that both Haydn and Mozart occasionally accepted the problematic tones in natural trumpets in favor of achieving the desired brilliance in texture.