I have two CableCard setups running here, each in it's own HDHomeRun Prime (three tuners per Prime). I also have Cisco SDV tuning adapters for each CableCard... you will as well (the Roamio appears to be compatible with SDV tuning adapters).
Whether the CCs and TAs are in stock will depend on your local office's current stock situation. When I picked up my first CC/TA pair, the Matthews office had the TA but no CCs... I had to trek over to the Arrowood location to get the CC. When I picked up the second CC/TA pair, the Matthews office had both in stock. I should add that my son had a more mixed experience up in Raleigh. He also has two Primes... the first CC he picked up was defective and he had to wait two weeks for TWC to have another available. His second time was more like my experiences.
The activation process was time consuming but painless both times (calling TWC's national CableCard activation center). The most recent activation I did was handled by a rep named Dakota... he was extremely knowledgeable about the process as well as my HDHR tuner. He had me check HDHR diagnostic screens several times along the way and and stayed with me until it was verified that all subscribed services were working. Process took about 30 minutes after a 2-3 minute initial hold time.
A single multistream CC and TA will handle all four tuners in your TiVO.
Edited by jcalabria - 9/1/13 at 5:24pm