CD 6000?
There is CDX, CD50 ,CD5500, CD6500 and CD7000.
I don't know where CD6000 fits in.
I'm the owner of both Beosystem 6000 and 8000.
I love the systems each for different reasons.
I also have the Beosystem 6500 which sounds good but are so much better in the remote and linking department than 6000 and 8000. Then the space taken is also great.
For the 6000 and 8000 you get 3 units being Beocord, Beogram and Beomaster. You can ad a CD player but loose any remote options.
The 6000 and 8000 has something that the later 5000/5500/6500/7000 systems and Beocenters does not have which is power! The high output of the amplifier sections are not present in future B&O onwards as it went to Beolabs (active speakers with ampfliers built in).
This make both Beomasters great, dynamic and loud able to handle any kind of music. I can play Metallica's Death Magnetic on the CDX to the Beomaster 8000 and it sounds great. Many complains of the loudness and hates the mix on that one.
Disadvantage of the 8000:
Heavy, needs service when you find one, to wide for any normal B&O stand, hard to find linking and IR parts for Beolink 1000 option, original stands are hard to locate, white edition very much less common
Disadvantage of the 6000:
Volume control, hard to find linking and IR parts for Beolink 1000 option, the 2035 remote was optional so not every unit has the printboard installed or come with a 2035 remote.
They do sound very much a like and there is not a huge difference between them. In fact I got a Danish review and the 6000 was rated higher than the 8000!
They both have their own terminal which works great. The Beolink 1000 and Beo4 for that matter can control them but the IR kit is hard to find complete and Beoworld has yet to find a member with a working one.