I have an older Bachmann Spectrum HO DD40 vintage 2001.  I also own a newer Bachmann Sound Value DD40.  I would like to add a decoder to the older unit so here are my questions:
Can I purchase the Sound Value decoder from Bachmann?  Soundtraxx does not sell them.
The Sound Value DD40 has resistors and capacitors installed.  Can Bachmann provide the values for these?
Can Bachmann provide installation instructions or advise where to get them?
Thanks.