Grandstage Piano uses Kronos technology – 7 of 9 Kronos sound engines. It's also supposed to be a SV-1 successor. SV-1 has been produced for several years already and is quite popular and affordable but its functionality is anyhow limited which is no good for a modern device, especially seeing other competitors.
In addition to the classic sound Grandstage’s got an impressive analog complexity. This instrument can boast its refined sound range. First of all it’s Italian Grand (Fazioli presumably), Yamaha Upright, German Grand, Yamaha Grand, Austrian Grand, Berlin Grand and CP-80. As it was already mentioned the instrument will operate using 7 sound engines including SGX-2, EP-1, CX-3, HD-1, AL-1, Vox Organ and Farfisa Organ. The keyboard goes with 400 factory presets.
Grandstage will become available in 2 versions: 73- and 88-note. Both of them are quite portable and solid which helps it fit in with the aggressive stage environment.
Talking about the correct release date and price – Korg developers promise to announce that together with the rest of the details very soon. Though you may put $2000 as a reference price.