Royal Purple is definitely some good oil. It's pretty expensive in most places though. I use Mobil 1 5w30, but 10w30 will work just as well. It doesn't get too extremely hot or cold around here so weight won't really matter. My philosophy behind it is, if the synthetic stuff is rated for twice the mileage then you will definitetly be protected up to 3K miles reguardless of how you drive.