I want to replace my Series-2 box with an HD-Tivo . 1: What is the quality of the OTA tuner. 2: Can I use one cable card and use the OTA feed for the second data source? 3: Will the guides be combined. 4: Will the HD-Tivo compress the OTA feed for buffering or pass it unchanged. 5: Can I watch OTA while recording cable or vice/versa. 6: Can I watch a previously recorded program and record both a OTA and cable program at the same time?