There is a lot more to PS-32 then P-2, and the comments so far have not fully grasp those differences.
The PS-32 is DCS and DCC capable. While not everyone's cup of tea, there are DCC operators out there.
For 2 Rail DC folks, the PS-32 is NOT polarity sensitive. It can detect DCS signal on either rail.
Because the flash file can be changed by operator, you can get other features like quillable whistle without requiring a special Flash PS-2 board. So if you where upgrading a Bigboy or Triplex as an example, or that N&W J, you can load the PS-2 3V file with QW and you get that function. That would not work, with the old PS-2 3V kit.
If your installing in an ABA set up with slave, you actually have a direct port for motor sequencing that allows a better motor signal to be sent to the slave board for enhanced slave operation.
Having said that, unless these are features you need, no need to upgrade a PS-2 3V or 5V to PS-32, but if your upgrading PS-1 or other manufacture items, PS-32 is the only kit available, once the PS-2 3V kits out in the retail market dry up.
Unless you go to an ASC who does custom installs.
Alan to answer your older question about original PS-3 boards, yes they could always load a PS-2 3V sound file. So that is not new. G
