I'd recommend buying new / either the ferrite magnet 416 or the alnico 416-8B if GPA releases it for sale . M19s use front mounted woofers .

Personally, I try to keep purchases to ferrite magnet ( or neodymium ) types to avoid just this type of remagging fiasco that's plaguing Pano .

- Something else to consider ( long term ), is how long will GPA continue to be in business .
- I have yet to hear any talk of a succession plan ( which is pretty critical in a micro business like Bills ) .

<> cheers