Royal purple is really good stuff. but not what they recommend. Just have the dealer service it, that way no problems should something go wrong. Plus, Nissan's filter prevents the oil from flowing back after shut off. That way when you start, it's not a dry start. Not sure other aftermarket filters promise that.
You can always use royal Purple after the warranty with good results. It is the shit!
I also recommend you do us a Poster modeling your x! Am I wearing you down yet?

MC