Couple things... in my opinion no need to change to fresh oil just to store a car... especially if you plan to change oil again come spring. Solid waste of money with zero real benefit imo. If youre worried about the oil sitting all winter and having a rough start up you may as well just swap the oil while its in storage right before you start it up for spring. 5w50 is too thick in my opinion and ford only makes the recommendation for track pack cars under the assumption that they will be abused on the track so the thicker oil will be more resistant to higher oil temperatures when pushing the engine hard. It does not circulate as well through the engine in some cases... especially under docile driving conditions.
2014 GT 5.0 | Premium | 401A | Roush A/B