I use a California Car cover regularly (these days my car is driven on the weekends and sits outside in the driveway during the week). My first one (the best you could get at the time) lasted almost 3 years. UV rays compromised the material, the seams were still holding strong. This time I bought the most durable one (wasn't available before IIRC). The fit and quality are superb, even though some may gripe about the price. For me, the price is worth it (think of it as an insurance premium cost spread over 3+ years) considering how well the paint and tires hold up in the S. CA sun, wind, and (occasional) rain.
Oh yeah, and they will alter to fit any body mods that your car has.
70 to engine rebuild faster than you can say "poofff!"