I've always used Mobil 1 in all my vehicles......from my GT, to my Cobra, to the GTO, and now the L and have always been happy with it. I ask the same question, why non synthetic??? It's always better to spend the additional money on good oil in my opinion......just my .02
^--- Sames, Mobil 1 saves lives, I use it in all my vehicles.
Quick story, a buddy of mine was about 1/2 mile away from his house in his low low pickup truck, it was really late at night and he bottomed out and busted his drain plug on the oil pan, since he didnt have AAA and was so close to home, he limped back knowing that he was loosing all of his oil. Long story short, due to the maximum lubrication of the Mobil synthetic, the engine was not harmed at all.
Moral of the Story: Run synthetic, it is worth the extra money