[Byakuya]

Whenever available, the GF-5 Mazda/Idemitsu Moly 0W20 would be tops on my list. The slippery chock full of molybdemum amount in this syn oil is highly beneficial to the superb fuel economy numbers and low wear/low friction properties for the long stroke 2.5L. Well formulated by Mazda engineers for the Sky-Activ series engines. My fall back/2nd choice, the Mobil 1 Advanced Fuel Economy (AFE) (5qt jug) from my oil stash..

For warranty requirements, I'd stick to 0W20, plus there is no 5W30 Mazda moly..

Everything he said. There shouldn't be a debate when it comes to brand new cars and manufacturer knows best otherwise they wouldn't bother putting it in the manual.

0W20 moly all the way for me.

 

[Byakuya]

In my humble opinion, unless there is something very different about Mazda's skyactive engine, all of these are pretty much equal.

That's just the thing - there IS something, well a LOT of things, different with the Skyactive engines. Sure, they'll be just fine without the Moly, but with all the new lightweight parts and precision and quality of each piece, wouldn't you want to do anything possible to keep it running as well as possible? Even if moly doesn't do anything, tough to say, but it costs no more than your conventional oil and lasts just as long - I say why bother with anything else.

Just like Shell gasoline with the nitrogen - that's been proven to help engines but costs no more than normal gas - I make it a point to get shell any time I can because what's driving an extra mile for gas if it helps my engine go another 5000?