Yep, it's a crossfire-
If I didn't have to drive her up the ramps and take the plastic cover off the bottom of the car-I would take a picture of the "mysterious screw" it's not one of the screws that holds the oil pan to the engine-next oil change I will photo document the screw-maybe it's there in case one wants to install an oil pressure gauge-I have no idea!
I did use synthetic mobile 1 and the appropriate filter-no problems there-although I have a minor leak where the oil filler spout connects to the valve cover-and some minor leaks in both valve covers-should be easy fixes! The trans is manual so I just changed the gear oil-here I went back with oem spec oil as some have said that synthetic actually made shifting worse. My tip for trans oil change is the filler plug (14mm) is situated high in the tunnel and hard to get to so I had to modify my hex socket as an Allen wrench of that size is not readily available in my area-other than that it's quite easy to service once you figure out how to get under the car!
Thanks for the reply!