Unless all the old sounds have been reprogramed to make use of the uprated sound engine, (Highly unlikely as it would be too expensive to do and reduce compatibility with previous instruments) there will be minimal difference between them. (As mentioned in my previous post (If you would care to read it)

A PA1x voice on a PA2x or PA3x will sound almost exactly the same as a PA1, because it is a PA1x voice.

The D/A convertors and pre-amps in the output stage also make a big difference to the sound. (If these have been improved then there will be a notable sound improvement to PA1x voices, if not then there won’t)

Bill