Haven't seen much discussion on this oil. Pennz is marketing it as a synthetic blend and for the increased demands of heavier, hard working vehicles. Is there anything really special about this oil compared to their regular 5w-20 Purebase dino? Also wondering about Valvoline Durablend 5w-20. Yesterday, while at Autozone I noticed the bottle states not only GF3 but also GF4 and something called ACEA-1? THe Durablend 5w-20 was $2.88 / qt.