Well, you've just started the discussion and I've moved your thread to the "Upgrading Other DVRs" topic which is probably a little more appropriate.

Hopefully, folks working on this will post their findings here too, as there does not seem to be much (if any information) readily available on the topic.

DVRplayground would be a good place for this discussion to be had, so please update as your learn more.

For answers to commonly asked questions, please refer to the
InstantCake Instructions and Release Notes,
Official InstantCake Discussion Thread, and the
Official PTVnet Discussion Thread

R 15 is great for obtaining a 160 gig HD for use in a TiVo :p

 I have the HR-250 and wanted to know what to do to get HR-250 on my home network.

Without DirecTV service, there is nothing you can do with it. DirecTV DVRs can only record the direct digital stream from the satellite.

TechLore Blog

HR10-250, Samsung SIR-S4120R, SIR-S4080R, 2 Philips DSR704s (one connected to a Slingbox A/V). One box used the "Zipper"; rest used PTVnet to enable networking features.

You can network you DVR. You can not save any movies to your computer at this point. You also can only network your HD DVRs together to share what you have recorded. It only works on HD DVRS right now. You also need the last software which you can install by resetting you receiver and at the hello screen press 02468 to force the down load. If you see multi-room under the system setup menu then you have the latest update. Each receiver should have their own IP address as well. I have not tried this with any of the older models, but if you have HR23 it will work.

Yes the need to be net work or you can wait till after may 13th 2010 and call directv and have then connect it for you. New upgrade will be ready then and they are calling it connected home.

any idea of bandwidth needed for SD or HD?

The whole home upgrade from Directv isn't a bad idea, just poor implementation. What was the one big perk about DVR's? For me it is being able to skip the commercials, or go back to repeat a part that my old man ears didn't hear, but you won't be doing that from any of the satellite receivers on the Whole Home DVR. Cause they don't have access to be able to do it. Working at DISH Network I stay on top of all new tech by all the providers, cause I love to see the new and cool things they all come out with, but unfortunately this is not one of them. I might have 4 tv's hooked up to DISH through 2 DVR's but the only th ing I lack is being able to play the same DVR on all of them, and I can watch my recorded DVR's and live TV anywhere using the sling adapter. I think Direct is still a couple years behind the pack.