Steve,
can an E-8 ABA 5 v sound file be downloaded into an F-3 ABA without affecting the operation of the engine.
If the F-3 is also a 5 volt PS2 engine then the file can be loaded into it. If it's a 3 volt PS2, it cannot.
If the F-3 has the same size driver as does the E-8 (I believe that it does, since all MTH diesels are supposeed to be the same size) and also has the same gear ratio as does the E-8 (it may or may not), then the SMPH speed should be unaffected, as well.
If the E-8 has the same or more features (markers, number board, interior, etc.) as does the E-8, it should operate the same.