So I've spent the last couple days researching oil and basically i think my brain is fried.
My manual for the 99 r6 says to use 15w40, but I found some rotella t 0w40 synthetic at crappy tire I might wanna try out. From what I gather the first number number really doesn't mean much as it's just how light the oil is. So in theory wouldn't a 0w40 oil protect more because it's lighter, more susceptible to varying climates and will run through the engine easier on start up. I mean at running temp it's all the same anyways at 40. I also hear people racing with 0w40 for increase hp and better mileage? Any thoughts?