If you just got the car, and if you don't know the car condition, and if you never use synthetic oil in the engine...
I will recommend blend/semi-synthetic oil... instead of full synthetic.The reason behind this is because the seal in your engine might have been degrade over years, and the good cleaning engine in synthetic oil might wash away the dirt that help to seal your engine. Therefore, seme-synthetic/blend is highly recommended.
Here is to the thread about engine oil from our holy PalmerWMD.http://www.nissaninfiniticlub....t=oil
Filterhttp://www.nissaninfiniticlub....t=oil
Here is a good source of engine tech info:http://www.chris-longhurst.com....html
Enjoy
p/s: For my personal perference, I use Mobil 1 0-40, Mobil 1 5-40, Valvoline DuraBlend 10-40. Oil filter. WIX.