First, I just have to say that this is an excellent site with lots of great information about the many different types of oil and should prove very helpful should anyone ever need help. My question is....would it be better to run AMSOIL 5W-30 or AMSOIL Series 2000 0W-30 for 20,000 miles or to run regular Havoline, Castrol, or Chevron 5W-30 for 5,000 miles before an oil change? I would run AMSOIL oilfilters if I used the AMSOIL....otherwise, I would use Bosch brand filter with dino oil. Keep in mind that I don't plan on spending the extra money for any type of oil analysis ever. Also, I drive a 2000 Nissan Frontier SE-V6 4x4 Automatic with the VG33 engine. My driving style is very aggressive and I drive about 20,000 miles per year with about 90% of them being highway miles. Thanks for any help!