switching over to Amsoil. which one should i get?

[rocket celica]

same as above.
I take it that amsoil is the best but what grade do i need to get.
I've bee n using 5w-30 mobil1 but I notice alot of people use 0w30 on amsoil. I live in southern cali. What should i use?

[1Highlander]

you can use the 5W30 or 0W30. The formulations are a bit different, and the 0W30 is designed to go longer between oil changes (also is more expensive)...