Is it bad for your TV to use the native mode on HD receivers? I get the best PQ this way, but whenever I switch to a channel that uses a different format, I hear relays clicking, etc inside the TV.
It depends on the DTV you are using. Most convert whatever HD resolution they receive to their native resolution w/o any fuss. A few are strictly 1080i only and won't accept a 720p signal. Other than that, this shouldn't be any big deal.