My car will be kept outdoors unused for 6 months during winter...should I use a premium car cover or leave it uncovered? Paint color is silver.

Always keep the car cover with a good cover, make sure you give a car a good wax before putting the cover on. I would remove the battery and store it in the house. Make sue you inflate the tires to the correct pressure, fill the gas tank up and add fuel stabilizer such as STA-BIL.

You don't say where you live, but if it's in the snow belt a car cover is a must. Ideally you want to move it every so often to keep the tires from getting flat spots, and a float charger can keep the battery charged but does need to be plugged in.

Put Sta-Bil Fuel Stabilizer in fuel tank per instructions. Dis connect Battery. Below is a URL with tips for you, copy & paste to new browser window.

http://www.edmunds.com/car-care/how-to-prep-your-car-for-long-term-storage.html

http://www.wikihow.com/Store-a-Car

I like to jack mine up on flat level surface concreted and put heavy duty jack stands under it all four corners, just high enough to get the tires off the ground along with many of the tips on the pages I gave above )copy & paste them.