In my first Miata, an '02, I used nothing but Mobil1 full synth 5w-30 and standard filter. In the '02 Blazer I had and in my '10 Nissan Cube, I run Amsoil signature 0w-20 along with an Amsoil filter. In my BRG, it came with Amsoil Signature 0w-20 and Amsoil filter. 24k miles later, I swapped that out for Pennzoil full synth 10w-30 with a Bosch x3 oversize filter so I can go another 20k+ miles.