Its fairly easy to install. Since I have a top boot cover I'd rather not park the car remove the boot cover, put the top up then do the reverse. I can easily put this on in a few minutes and remove just as quick. I would obviously not do this if I am just going in and out of a place quickly, I have sun shades for that but this is for when I park the car and am going to be away from it for more than 30 mins or so. It appears to be rain proof as the poly-urethane coating would work well, and the magnets would keep it in place, I would probably make sure its alot tighter to try and prevent a bucket from forming in the rear if I suspected possible rain. The main reason I got this was to protect the entire interior from the sun. The Miata size seems to be the best fit for our Alfa's.