There are huge differences in oils even thou there all fully synthetic ,stug45 said:im using mobil stuff. how there is a great difference between other branded oils i dont know! a fully synthetic oil from a different well-known brand cant really be that different!
as long as its rated by people (ie my car hasnt blown with 5w40 fully by mobil-neither with 5w30 part syn) i'm sure theres no problem!!
get fully synthetic branded oil and change it regularly!
i do 6k changes, filter and oil.