The Magnificat in E flat major BWV 243a was composed by J.S. Bach in Leipzig for Vespers a feast of Christmas Day of 1723. The work is scored for soprano 1, soprano 2, alto, tenor & bass soloists; 5-part Chorus (SSATB) and orchestra of 3 trumpets, timpani, 2 oboes, 2 flutes dolce (recorders), 2 violins, viola & continuo.
The Magnificat in D major BWV 243 was composed by J.S. Bach in Leipzig for Christmas Day or Vespers a feast of Easter or Pentecost between 1728-1731. The work is scored for soprano 1, soprano 2, alto, tenor & basss soloists; 5-part Chorus (SSATB) and orchestra of 3 trumpets, timpani, 2 transverse flutes, 2 oboes, 2 oboes d'amore, 2 violins, viola & continuo. This is actually a revision of BWV 243a.
The discography pages of both Magnificats on the BCW have been revised and updated. See:
Magnificat in E flat major BWV 243a -Complete Recordings (20): http://www.bach-cantatas.com/Vocal/BWV243a-Rec1.htm
Magnificat in E flat major BWV 243a - Recordings of Individual Movements (4): http://www.bach-cantatas.com/Vocal/BWV243a-Rec2.htm
Magnificat in D major BWV 243 - Complete Recordings (137):
on 8 inter-connected pages, a page per a decade, starting at: http://www.bach-cantatas.com/Vocal/BWV243-Rec1.htm
Magnificat in D major BWV 243 - Recordings of Individual Movements (43): http://www.bach-cantatas.com/Vocal/BWV243-RM.htm
The revised discographies includes many listening/watching options as part of the recording details. When you click a link to video/audio, a new window will open above the discography page and the video/audio will start to play.
I believe these are the most comprehensive discographies of both Magnificats. If you are aware of a recording of BWV 243 and/or BWV 243a missing from these pages, or want to correct/add details of a recording already presented on the BCW, please do not hesitate to inform me.
You can also read on the BCW the recent discussion of these cantatas in the BCML (4th round): http://www.bach-cantatas.com/Vocal/BWV243-Gen8.htm