Placebo effect or not, this is a great oil. I think that my 98' Toyota Camry I4 engine really likes the thicker 30w oil. My only real signs of improvements are the quieter engine and far less vibration in the steering wheel. I will have a better feel for it as time wears on. Glad I took the time to switch. Now I have to get a loan and develop a huge stockpile of GC Gold.