FWIW as well, I have used the tire cradles for about 3 years with my Boxster previously with 18" conti's. I had to put away in the past for over 3 months at a time and they worked quite well. I got sick of the flat spots developing after just a few weeks during the summer while on business trips.

As for the fuel stabilizer, I have heard many different opinions, but never used it in the past and never had an issue.

One other good thing to note is if you are going to store for a while to put in some "humi-dry" or some other moisture absorber in the car. I usually buy it in a small plastic container and sit it inside a small bucket on the floor of the passenger side. Even though winters are generally pretty dry, you will get moisture build up and you do not want any nasty mold or other things growing in your car over the winter!