Lots of people use unsubbed DTivos hacked for MRV. Since you're not really using any of the DTivo's functions that would normally require a subscription or mirroring fee, you're not really stealing service, although I'm sure there are those that may have a different opinion on the subject.
You will probably neeed an access card inserted to avoid the nag that comes without having one in the slot and you should also consider having a sat feed connected to get rid of the "searching for sat" message as well. You'll also get a nag message about activating your Tivo service but that only shows up when you first access the Now Playing list. You obviously won't be able to watch any live TV on the DTivo unless you can't wait to see what's coming up next on the DTV info channel.
The answer is Yes, you can do it cheaply. Just don't tell us about the particular method you used since the authors of that script have expressly requested that it not ever be mentioned here.
Please don't PM me or any other members looking for personal assistance. You'll do better by posting (after you've exhausted the search feature, of course) and taking advantage of the collective expertise of the membership instead of a single individual that may or may not be able to help you. Thank you and enjoy your stay at DDB!