Looking for some thoughts here—I’ve got GT3 buckets in the car, so the stock seats are in my basement storage and likely will not go back into the car for a few years. I’d like a large zippered plastic storage sack to keep the seats clean and odor free, but have yet to find anything. Any suggestions?

How damp is your basement? Unless you have good humidity control I’d avoid any non-breathable material like plastic. I stored seats in heavy garbage bags for a few years, when I finally took the seats out to use them, they were covered in mildew.

Clean them ,liberally use some leather feed or similar product to protect and hydrate the leather and wrap them in some old cotton bed sheets not plastic