I have had two Covercraft Noah's (first one finally gave up after six years) on my S2 which has always sat outside since I bought it eight years ago, no deterioration in paintwork and spider has been regularly put away damp and dirty, all I can say is its 30 year old respray must have been proper quality, however I wouldn't use one on a car with new paint or one in concours condition, mine is no trailer queen but it shines up nicelyFor what car? I have a spider cover, the Noah by Covercreaft that I used for a couple of months indoors. Still looks brand new. Centerline sells the for $300, looking for $200 for the cover.
Centerline International is the leading supplier of restoration, performance, and maintenance parts for all Alfa Romeo models frwww.centerlinealfa.com