I use Castrol GTX after using all sort of oils including the high end ones that include Semi synthetic.
Though its only API SG but i think the oil is much better than most oils i have used. I feel this after using this engine gives low noise and the oil level never drops.
Good morning startup even in 0c.
And its cheap to just 800Rs for 3L.
I change it after every 2500 to 3000.