I have an 02 DeVille(with 104k on it) that is sucking up 1qt of Mobil1 5-30, I want to switch to some type of high mileage oil. Can't decide on what to go with my 3 choices are Mobile 1 high mileage, Valvoline Syn high mileage, or regular dino Valvoline high mileage. Would their be any disadvantages with going with the regular dino, since the car has been on a M1 diet since new. It's just killing me to buy 8qts of M1 to go 3k. I can get the Valvoline dino HM for $13.50 for a 5qt jug. Looking for info on what you guys think. This is my first post here, long time lurker..but this DeVille's oil consumption is killing me.