As a 911 Targa owner, I use Mobil premium gasoline as specifiec. i was always told that Mobil gas and synthetic oil is the best. Being a Ferrari F1 fan, I can understand why the dealers and company recommend Shell and Agip as suggested gas and oil. Is Shell gasoline any good? Your thoughts would be greatly appreciated. I ask this because I am waiting for delivery of my Gransport. i am trading my Targa for it and curiouos if I should start putting shell gas into my maserati.