Thanks sir. How about Valvoline? Is it a good one to go with?
Also an update; I went to the previous mechanic today for the engine check light scan and it came with error P0171 SYSTEM TOO LEAN (BANK1). Had to go back to him as I already paid him for the tuning and the error came in afterwards. He said that get some Hi octane fuel in tank and drive for a day and then he will check it again. I did refuel some hi octane as well for the sake of it and as it doesn't cause any harm.
I might not go back to him but Irshad bhai day after tomorrow. InshAllah