I'm looking to buy a used piano but it has a player system installed, which I don't need - the system looks obsolete anyway, uses 1990s style diskettes. Anyway, does the presence of that system adversely affect the responsiveness of the keys, and the sound? Thanks, Lou

There is a significant difference between (electronic) player systems. To be able to determine the capabilities and limitations of the system you're looking at, you would need to find out exactly what piano and player system is involved.

If you don't need the player system, it may be possible to remove it, at least partially. Again, it would depend on the system as to how much can be done.

I would also suspect that having a player system might push up the asking price of the piano, so if you don't need it, you can probably find a similar piano at a better price on in better condition.

If the player does not record, there should not be any contact between the player system and the piano mechanism when the player is not being used. If the player system records, there might be a microswitch which would have a minimal effect on the action, but most modern systems record optically.