I think siphoning gas out of the tank is about the only worthwhile addition to the procedure that this discussion have so far produced. It would definitely saved a good amount of time, mess, and gasoline. Things like removing a tank really sounds easier than it really is. For one, just one rusty bolt or nut is enough to ruin your day, to put icing on the cake a broken bolt is even worse. After the tank comes off, for installation, sometimes (chevy trucks) have this really awkwardly positioned nut that you have to fish the bolt through, again very painful process.