About 6 months ago, I installed a 2nd hard drive in my DirecTV HR-10 250 receiver. It doubles (possibly more than doubles) the storage capacity, was an easy install and works 100% perfect. IMO and in my experience, this is a great web based company:
http://www.weaknees.com/hughes-hr10-250.php
http://www.weaknees.com/hughes-hr10-250.php