synthetic oil

I have 2012 CX-9 Touring AWD. So far ran 50k. While going through the forums , I realized that CX-9 has significant issues with the transfer case and I really need to take care of it. However, I came across some doubts - 1. Transfer case has only one plug. I have to pump out fluid from it...

I apologize if this EXACT thread is open but i have looked, a lot. Some History. I own a 2004 Mazda 3HB manual touring with 120xxx. I purchased it like so becuase it is in beautiful yellow condition, rare with one owner fully loaded. It uses regular oil, 87 octane. Dilema. I live in Boston and...