sorry for the stupid question, still learning. anyway buaght that oil only to find on my supra that is says 10W-30 amongst the japanese writting. What i want to know is should i use 10W-30 oil? does it really matter what you use? is it more to do with where you live? ie cold/hot climates? i'm in tas where it's pretty cold. but it can get pretty hot in summer. I don't want to harm the supra life or performance.