As for winter storage I only put some additive to fuel. Myself, I don't like the idea on letting the car sit off the wheels for any period of time.
I did buy a outdoor rug with rubber on back to keep moisture from getting to bottom of car. This has worked great for me. I used to find the whole bottom of the car dripping wet during the cold months. Large enough so whole car is on top of it. Hook up battery maintainer and cover the car and only start it when it can be ran up to running temp so all moisture is removed from motor and exhaust. I normally start it four times during winter and take it for a run.
tom