Has anyone tried this Mobil 1 Truck and SUV 5w-30 synthetic oil? I grabbed it at Wal-Mart and put it in our two '99's that were running Mobil 1 0w-30. It seemed to make an improvment in performance in terms of engine noise level and improved acceleration. Anybody else have any info on this version of Mobil 1? Maybe it's just my imagination but they seem to claim it's heavier duty than regular Mobil 1 and formulated just for SUV/Trucks.