I use Brad Penn. Granted I don't take my car to the track. I only have 39000Km,(24000 miles). I did a lot of reading here, and you'll get a thousand opinions. I could put any oil I want in my GN. I only change my oil a couple times a year. Money is no object with the oil that protects my original flat tappet cam. If I thought Royal purple would work better I'd use it. All I can say is whatever you choose.... go with it. Don't second guess yourself. I put 5 quarts of Brad Penn, and a bottle of GM EOS(engine oil supplement), and sleep soundly knowing my baby is well protected. Dave