While it might not be the most popular suggestion, I'd definitely go with a truck roll on a first time install. Demand a tech that has experience with cable card installs. I only suggest this as you'll likely be stuck talking to countless Comcast CSR's that have no clue about cable cards, especially if it's a first time TiVo install. At least with a truck roll, you're (almost) guaranteed to get the TiVo working before the tech leaves. They also can't blame you for any configuration issues. Even after all these years, I'm astonished at how few Comcast techs have been trained on cable cards. I had a VOD issue a few weeks back and it took 4 separate phone calls to finally determine it was an issue on Comcast's authentication servers. One of the CSRs changed an account flag that shut down my VOD. They were determined to send a tech, despite my resistance insisting that NOTHING on my 3 year old TiVo's had changed. I'd pay the $20 or so to ensure they get it knocked out in one visit vs. wasting HOURS of your time talking to different CSRs.