Mine (4/4 sport) has lived outside on the drive for over ten years now under a variety of covers. Metex by Hamilton for eight years - they last about 2-3 years. And a Covercar one for the past two years. Both of these have non- scratch inner layer and are breathable. You can put them on a wet car but not a dirty one as the muck will then scratch - if in a hurry I just use a detailer spray to wipe off dirt on the points which touch the cover.
If you need details PM me.
