Hi guys, I just did the first (for us) oil change on my wifes 06 mazda 3. I was going to go with mobil 5w20 but it was going to cost an arm and a leg. I could have bought it by the jug at walmart but.........didnt want to the guy at the parts store hooked me up with amsoil xl series 5w20 for $8 canadian a quart, which is a wicked deal for up here. any thoughts on the stuff? Its not the guarenteed for 10 years and 300,000 mile OCI stuff, but its API rated, and says good for 6 months. thanks.