Erard and Pleyel from KIViR will sound as great as Kremsegg's grand models, I presume.

I have only one request. A1896 Bechstein version tuned for classic. Even pianoteq Pro do not have adjusts for the shape of hammers, and other few things that maybe could help to push Bechstein to classic. A spe cialclassic Bechstein  preset would be welcome.

I was confused in the beginning, too. It looks at first like there are duplicate instruments, but there are really none.

KIViR includes an 1922 Erard, 1926 Pleyel, and an 1896 Bechstein. The Erard in Kremsegg 1 is an 1849 model, so it is much older. Likewise, Kremsegg 2 includes an 1899 Bechstein and and 1835 Pleyel. So the only instruments which could be similar are the two Bechsteins. Which they are not, they sound completely different. How much of this is due to KIViR currenty essentially being PTQ2 instruments, I cannot say.

Apart from that KIViR includes several piano predecessors as well as the Yamaha CP-80 electric grand.

The website says:
https://www.pianoteq.com/free_stuff
Free stuff
The KIViR instruments are currently in the process of being fully updated to version 5.
The new and much improved KIViR instruments will be available in a couple of months.

The KIViR instruments:
Clavichord: Neupert
Cimbalom: Kovács
Harpsichord: Grimaldi
Harpsichord: Blanchet
Pianoforte: Walter
Pianoforte: Schöffstoss
Pianoforte: Schmidt
Pianoforte: Schantz
Pianoforte: Graf
Grand piano: Pleyel
Grand piano: Erard
Grand piano: Bechstein
Electro-acoustic piano: CP-80

Kremsegg collection 1:
Dohnal pianoforte
Besendorfer grand piano
Erard grand piano
Streicher grand piano

Kremsegg collection 2:
Broadwood pianoforte
Pleyel grand piano
Frenzel grand piano
Bechstein grand piano

The fist is in purpose : Kremsegg collection is intended as a commercial add-on of some historical late 18th - 19th century grand pianos.

KIViR is intended as a non-commercial "restauration" of historical instrument, with "historical" being more loosely defined than in Kremsegg collection : some instruments are way older (early 18th century, or modern reproduction of even older instruments), while others (the grand pianos) are even more recent (late 19th century and even 20th).
KIViR instruments are virtually "donated" to PTQ by their owners, while Kremsegg collection is issued from a partnership between an institution and PTQ.

This is regarding their status. But, as the OP said, besides their commercial status, the two ideas seems quite similar. What is the "compelling reason" of having BOTH KIViR and Kremsegg ?

Why, quite obviously, because each modeled piano is different from one another !
Even if, with Kremsegg, we have an Erard, a Pleyel and a Bechstein as we do in KIViR, they're far from being the same instrument.
In some cases, as in Pleyel's and Erard's case, the time span between the Kremsegg versions (respectively 1835 for Pleyel and 1849 for Erard) and the KIViR versions (1926 and 1922) is so conspicuous that one can hardly compare them, even though being from the same manufacturer. They are as different as a Fazioli and a Steinway could be.

For example, I do personally love the 1922 Erard sound, even if it is marred by all the primitiveness of a PTQ 2.0 modeling (I can only dream about how it will sound with the new update. I guess it'll become my main piano !), while the 1849 one, though having a purer sound, is less appealing to my ears.

Saying that KIViR instruments (or, at least, KIViR grand pianos) have no "compelling reason" to exist on PTQ - and to be updated - since we already have the Kremsegg pianos would be like saying that - if a Mr. X would want to "donate" the model of an old Steinway American D from the 1930, or of a Bluethner from the 1950 - PTQ should refuse to model it because there already is the D4 and the Grand Bluethner !

https://www.pianoteq.com/kivir

History is pretty neat and deserves a page:

http://en.wikipedia.org/wiki/S%C3%A9bas..._the_piano

It will take some months to upgrade KIViR, I believe.
Hope Kremsegg salles go well and help to Modartt invest in the creation of new instruments.

Modartt it's working on that.

I have been using PT4 for a bit more than half a year now. I bought it last year more or less specifically because I fell in love with the Blüthner grand. (And for the U4, since a decent upright is also nice to have.) I have just updated to PT5, and apart from a few built-in presets having changed their name, everything seems to be perfect. The D4 seems to sound a bit more bright, although I have not made detailed comparisons. I think I also like the new K2, but I have not tinkered with it yet.

I use KIViR not quite regularly, but I do occasionally. It just is something different to play Beethoven on a Pleyel or Erard than on a modern grand. So I think I will check out the Kremsegg demos, thanks.

does anyone know the exact differences between Kremsegg and KIViR? The idea seems (at first glance at least) to be pretty similar, and at first I thought Kremsegg would "just" be a revamped KIViR updated especially für Pianoteq 5. But on the KIViR page there is a comment that the free addon will also be overhauled for Pianoteq 5.

Kremsegg offers a subtly different and slightly larger selection of 8 classical pianos (with a special emphasis on 18th, 19th century grands, it seems), so much seems to be clear. KIViR includes 7 classical pianos, but also piano predecessors like clavichords that seem to be completely absent in Kremsegg. So I guess one major difference is the scope. Does anyone know if there is also a noticeable difference in terms of quality?

Regards,
Robert