Just to clarify the differences between between the English and German versions of the new box set ("The Catalogue" vs. "Der Katalog")...
Kraftwerk's first two electronic albums (this is excluding the early prog albums), "Autobahn" and "Radio-Activity" were only released in one language worldwide. "Autobahn" was only recorded in German. "Radio-Activity" was recorded as a German/English hybrid. It was titled "Radio-Aktivität" for the German market, but the music is the same as on "Radio-Activity." For these remaining albums, both English and German language editions were issued (I am not counting some of the Spanish and possibly French editions that were also recorded):
Trans Europa Express (aka Trans Europe Express)
Die Mensch Maschine (aka The Man Machine)
Computerwelt (aka Computer World)
Electric Cafe (same title in Germany, but with German lyrics)
The Mix (same title in Germany, but with German lyrics)
The German "Der Katalog" will include remastered versions of the above albums with vocals in German. In my personal opinion, Kraftwerk's music sounds MUCH BETTER in German than in English. The lyrics are much more direct and effective in the band's mother tongue. The emotional (or lack thereof) content comes across much better in German. Despite the slight price difference, I would HIGHLY RECOMMEND buying "Der Katalog" from Amazon Germany instead of the US or UK editions. Again, in my opinion, this is the true way that Kraftwerk's music should be heard and experienced! ;-)
As for the mastering quality, I cannot yet speak to that. As I got tired of waiting for the remasters, I broke down and paid a hefty pricetag for the 2004 UK promo (I know, it's in English). I am no audiophile, but the sound quality sounds pretty good to me.
-Mike