Hi James, hi everybody!
Was the new name changed only because of the introduction of the silver faceplate?
No.
The only thing I can think of is that our German distributor used slightly different names in Germany for the preamps.
james
James, you are right. Sun Audio, the German distributor, introduced the BPS-labelling to distinguish an improved version of the BP 25 (we both know that they are very creative in (re-)labelling...

). It was the shift from the BP-PSR to the MPS-1 as the external power supply and some improvements on the components inside. I got my BP-25 upgraded at Sun Audio and was able to acquire a MPS-1 (in Australia) to make my BP-25 a so-called BPS-25.
How would you comment on the changes on the BP-25?
Comparing the two power supplies, the MPS-1 makes a better impression than the BP-PSR, only beaten by the MPS-2 that's part of the BP-26.
I hope this helps.
Cheers!
Markus