CZJon
Yes PS makes both. PowerService in the white jug is a c-tain improver/fuel conditioner. They make a silver branded jug for injector cleaning and the 911 red quart bottle, for serious jelling/water issues. Take a look at their web site. Wall Mart here carries it as well as my Co-Op. You will find it in various truck stops too.
My water came from bad fuel, but any time you get cool temperatures and humidity you can get condensation inside a tank, especially if it is close to empty.
Block heater is optional - I paid extra and it is worth it where I live. I believe you can add it later if needed.