I am about to change the oil in my 07 Audi A8 4.2 FSI. Car has 70K on it and I'm aware that it calls for oil with the VW 502...I was going to use Castrol Edge, but should I use 5w-40 or 0w-40? Both meet the standard but being in CT and winter coming is there any advantage of going with the 0w-40? What would be the best oil to use for this engine, I plan on keeping this car for a while. Thanks for all the help.