Just my opinion, but if your car isn't perfectly clean 24-7, putting on and taking off a cover will leave swirl marks in your paint. A little dirt is ground into the paint everytime you use the cover. Lots of wax might help MINImize the swirl marks from getting to the clear coat, but they will still appear in the wax which will be easier to deal with later on. Sorry, but I'm not a big fan of covers.
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Ken
Denver, CO
A friend will come and bail you out of jail, but a true friend will be sitting next to you saying, "Damn, that was fun!"