John, What do you mean by doesn't alter it's behavior like the PS-2 does? The sound file is the sound file. It will alter the behavior of the locomotive.
PS-3 boards can accept PS-2 3V sound files.
Time will tell on these upgrades. Diesels should be the easiest since that is one board in the engine. Steam will require 2 boards. One in the engine and one in the tender. Since it only requires 6 wires between the 2 to communicate it shouldn't be too difficult, but I imagine there is no equivalent harness yet. Should also be interesting how the LED lights play out. A replacement LED from MTH is $10.
Components are getting harder to get. The big issue with PS-2 is that one of the components on the Power Supply board is obsolete. New PS boards were revised to REV E. The printed circuit was modified to accept the new pinout of the new component.
The other issue is the tach readers are obsolete. G
