Ok, I'm not a chemist so layman's please; Castrol Edge 5w-30 Castrol Edge HM 5w-30 Castrol Edge EP 5w-30 Castrol Magnatec 5w-30 Cheapest is Magnatec at $21.44 Most expensive is EP at $24.48 Walmart prices Can there really be much differences between these oil at "basically" the same price? I have a 18 F150 3.5L and usually use Edge 0w-40, but I just want to switch it up, and actually use the weight Ford recommends. But 4 different 5w-30 weights, and thats just in Castrol brands... I know Magantec has good UOA's but is it any different than regular Edge? At $1 difference, can it be?