Should I continue the quest of using Synthetic oil in my car? I am having oil leak problems. My car has 70K+ miles on it, is it safe to use a regular weight on my car? And also will it cure most of the oil leaks? What kind of oil do you guys use on your 96-98 cobras? Any help in the oil department would be greatly appreciated! Also I have never had a car with synthetic oil, can I just empty the oil then pour in regular? What effects does this have on my vortec sq trim s/c? Was the previous owner using synthetic because it has a supercharger? I know a lot of questions, any answers would be great! thanks