Here's my story why I use Amsoil, I would like to say that you can use any oil your heart desires.
A long time ago in a galaxy far, far away......... oops sorry, wrong story.
I've used Amsoil since 1985 in a variety of cars. Everytime I would use any other oil, Mobil 1, Pennzoil, Castrol etc.. my car would need some oil by the time 3,000 miles came around. With Amsoil never did I have to add a drop.
My last car was a Celica GTS, I tried Mobil 1 just to save the time of ordering through the mail and lo and behold , 1 quart at 3,000 miles. Went back to Amsoil and no more problems.
I would go 9,000 miles or one year(I don't drive that much), with a filter change every 3,000. Never had any problems.
So I'm sticking with what works for me.