Disklavier

Hi, we just joined this forum as we purchased a used DGA1.  The piano should be delivered in a few weeks and now begins the fun part of researching more about what this piano can do.  Honestly, I'm a little overwhelmed by the files types and do have a few questions:
1.	Is the DGA1 upgradable with a DKC-850?  We're primarily interested in the steaming radio, as software for the piano isn't cheap. 
2.	How is the Disklavier Radio?  Is it worth the subscription?
Once again, thanks and we're really looking forward to having this piano in our household.
Weiner Family