I have two jeep 4.0L's one 130k and one 80k. Both use an oversized motorcraft filter which I think I am going to stay with. I usually do 4-5k OCI's which I am going to stay with since I have about 50% of the time I am in slow traffic. Which one would be better rotella T synth 5w-40 or castrol GTX HM 10W-40. both are about the same price.