Welcome i just did the same thing finaly started posting, im sure you already know but be sure that you have the right 4g64 there is a narrow and wide block only one will work in the car!
Well the picture is super small but that would be the coolant "neck" and if right under that has oil i would check the valve cover gasket make sure thats good/ no cracks in the cover
Do you know witch 16G it is? I loved my 16g on my old car one of the best turbos for these cars for the street! As long as you can stay away from the big HP numbers haha