Depends where you are. OZ and Canada have a few, but in UK & Europe, it's rarer.
The PE400 is becoming hard to find in good shape.
The NOS con-rod is unobtainable.
The larger T/X magneto is becoming very difficult to find.
The rear fender (NOS) will cost you a mint, if you can find one on the planet.
Best PE400 on the planet? Have a look at Fabrice's effort here:
http://pureenduro.free.fr/Rest/pe400tfab.html