Only MRV compatible receivers are all current HD/DVR's, all current HD receivers except for the H20 (but that is not used on new installs) and one standard def DVR the H22 which will automatically become an HD/DVR on an HD system.
With a new install you will get 1 HD/DVR and 1 HD receiver for free.
Additional HD/DVR's will cost $199 and additional HD receivers will cost $99 (unless there has been a change since I last saw)
If you even think you might want it, get it at the time of install or it will cost more later.
BTW, also ask for the cinema plus connection.
It is free hand has some really cool features.