I'm with BobCowan. When you hear: "But I actually and sincerely noticed the car running smoother, maybe 1% quicker, better mpg with
Amsoil." Yes, the guy THINKS he can tell a difference, but he REALLY can't (in my opinion, I'm not believing him). It is human nature, we all fool ourselves in many ways everyday. The lube
oil companies measure performance in environmentally controlled laboratories and look for small improvements over 100,000s miles. Consumers can only listen to the sales pitch and buy what they like to hear. Don't you think Chevy gets a kickback by recommending Mobil 1? Of course they do. Is it the best
oil for your Corvette? Probably so if it keeps the warranty intact. Any good quality
oil will work fine in our many engines. We will all have a much higher frequency of failure for other things than poor choice of lube oil. I always recommend buying whatever you want that makes YOU feel the best. That applies to oil, gasoline, cars, TVs and many other things.