We don't have a separate download for the 6000 loops. You have a lot of them in Mixcraft 5 already. I suppose you could install Mixcraft 6, and then load them from the Mixcraft 6 loop folder into Mixcraft 5.
It doesn't hurt anything to have both versions installed at the same time.
If you already own Mixcraft 5, it only costs $20 to upgrade to Mixcraft 6
, and the learning curve is not that steep.