Is Valvoline Extended Protection better than Valvoline Advanced Full Synthetic?

Yes, on paper. Extended Protection uses a stronger anti-wear additive package and is positioned above Advanced Full Synthetic in Valvoline's lineup. Both are API SP full synthetics, so the gap is modest for normal driving.

Can I use this in a car that requires dexos1 Gen 3?

Check your owner's manual first. This oil is API SP and ILSAC GF-6A but is not dexos1 Gen 3 licensed, so using it in a GM vehicle still under warranty could be a problem.

How many quarts does the five-pack give me?

Five quarts, which covers one oil change in most four-cylinder engines that take 4.5 to 5 quarts. Engines that take more, such as some V6s, need an extra quart.

Is 0W-20 right for my car?

Only if your owner's manual specifies 0W-20. Many newer Hondas, Toyotas and Fords call for it, but older engines often need 5W-20 or 5W-30.

How often should I change it?

Follow your owner's manual, typically every 7,500 to 10,000 miles with a quality filter. Valvoline does not publish an extended drain interval beyond that.