You must buy the parts from an aviation source. Someone
brought up that landing lights can be bought cheaper at
automotive supply stores than from aviation outlets at a
fraction of the cost. The FAA wouldn't hear of it.

Indeed. That's why the FAA doesn't hear of it, even though everyone
does it.

All preventative maintenance must be logged, including
updating the database on your GPS unit. So, if you
have updated your GPS database and did not log it, you're
not airworthy. This one caught a lot of pilots.

An FAA guy has to say this. He can't go around saying that you don't
have to follow the rules. However, I'd be very surprised if you can
find anyone who has been busted for not logging database updates on
their GPS. (Someone will now pop-up and repeat the nonsence about how
not logging it will void your insurance...)