Your na will be fine with pretty much all oils. Just use what the manual says to use.

For the record i use and have used 10w40 Nulon Fully Synth for years now in my GT and WRX.

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As Brunei has avg annual temp of 35c, I just changed mine with a L.Moly fully synth 5w-40 . . .methink the EJ20 is loving it . . .

Just swapped to Total Quartz Racing 9000 5w50 and got rid of Mobil Super S 10w40 ....engine is running so much better. Thanks Doug!

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06 STi: 337hp @23psi on E85...
06 STi: 309hp @22psi on 98ron...

Helps when you actually have oil in your engine to begin with dude haha.

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The one perkent...