The modifications required to install a solenoid-based player system are significant, including the cutting of a slot in the keybed, rearrangement/rebuilding of the pedal trapwork, and cutting notches into the front legs of a grand if the system is to play all 88 keys. With a particularly valuable piano, you would want to choose your installer carefully and inspect examples of their previous work. If you mention your location, one of us might be able to recommend someone nearby known to do quality work.
Playback performance of PianoDisc systems has improved a little over the years, but the optional optical recording technology they use senses key motion, not hammer velocities, so is inherently inferior to the recording quality you would get on a Yamaha Disklavier, Steinway Spirio, or other system that does measure hammer velocities. PianoDisc also does not support proportional (incremental) pedaling during playback, so subtle pedaling can be recorded but will be replaced by coarser on/off pedaling when played back.
If you want to avoid physically modifying the piano, you could consider an external "Vorsetzer" type system such as
QRS Pianomation OT. Recording/silent play capability could still be added separately and would be less invasive than the modifications necessary to install the playback system.
