I can answer one of your three questions here...
I don't know if the "kick back to live" bug is still there or not. It doesn't always happen to me.
If you go into the guide while watching something, highlight what you are watching in the guide and hit record, the 501 now creates a timer to record until the end of that event, so it will now stop recording at the end of the show. If you decide you want to record from the beginning of what you are watching, rewind the buffer to the beginning of your show, press pause, go into the guide, select your show, hit record and a timer will be created to record until the end of the show. But, it will start recording from the point you paused in the buffer. Also, you can now edit timers that are currently recording, so you can go through the above steps and then edit the new timer to end the recording a couple of minutes after the top of the hour (for example).
If you just hit record while watching a show, however, it will still continue to record until you run out of space.
Never heard any cricket like noises coming out of my 501. Maybe your hard drive is failing?