May I suggest Mobil 1 synthetic. My reasons, I use it, my dad uses it, my buddy who is a mechanic for Formula Mazda swears by and uses it religiously, and I know some of the guys at Exxon Mobil who make it. It is straight up awesome unless you want to try royal purple.

Source, I am a chemical engineer

 

+1 ^^^^^^^^ i posted early that thats what i use the mobil 1 racing 4t 10w40 synthetic, great stuff, theres a video on you tube or streetfire.net about a company that built a twin turbo gallardo for this guy (not a mobil one commercial) and one car that he rebuilt the guy used mobil 1 synthetic religiously in his heavily used street/strip car and when they did the motor build and took it apart the mechanic said it was the cleanest motor he has ever seen inside doesnt look like it was ever raced and looked new, he asked the owner what oil he used and said mobil 1 sytec and the mechanic said that they only use that stuff now lol i'll see if i can dig up the vid.. found it i'll post it under a new thread called "1 reason for mobil 1" in off topic section

 

Rotella synthetic. Cheap and well proven. Refer to the article in kilgores post. We all hve opinions and budies that did this or that...blah blah, the link shows the science and facts.