After following the site and having a few members help me initially, I've focused on 5w30 as my "engine oil of choice" for my '97 Explorer 5.0L V8. The truck has nearly 100K miles on it and has been well maintained, but I'm looking to choose the "best" oil, be it dino or synth to maximize its life. The specs below are of two dino and two synthetic brands that have received praise here (data was pulled from their websites). Cost is NOT a factor IF the higher priced oil(s) can provide extended life expectancy over their less-expensive counterparts. Chevron Supreme: 159 VI, -36c P.pt, 232 F.pt, 10.8 VK Pennzoil Multigrade: 160 VI, -42c P.pt, 216 F.pt, 10.5 VK Amsoil ASL: 182 VI, -51c P.pt, 230 F.pt, 11.7 VK Mobil-1: 167 VI, -45c P.pt, 224 F.pt, 10.0 VK I've been under the impression that a higher Viscosity Index and Flash Point are better, along with a lower Pour Point. Will either of those two full synthetics above help my new(old) Explorer live a longer life? What would you choose?