Well I just went 9,200 miles with Quaker State Ultimate Durability 5w20 and a Fram 15k filter in my 2003 Crown Vic P71. I believe I had to add 4 quarts extra throughout the whole time to keep it full. I was thinking about going with the Quaker State Ultimate Durability again but the Magnetic caught my eye so I decided to try it out. I used to run Castrol GTX in my old 93 Ranger 4.0 back in the day and the truck seemed to like it most. One interesting thing is that the 5w20 is full synthetic but all the other weights are syn blend. I'm going to do some homework on this oil but was wondering if anyone knows much about this oil. Is this a repackaged Castrol Syn blend? Thanks!