Today I changed the oil in my wife's 2000 GTP using GC for the first time. I had a stash of 16 qts before I started, but only 11 of them were green. I decided to use the Gold on my wife's car and the green in my Formula. I had been running M1 Truck and SUV previously and was very happy with it's performance. However, I noticed a BIG difference after changing to GC. The engine is MUCH smoother and even quieter than with the thicker T&S. The engine quietness totally surprised me. I expected it to be louder with GC. The engine feels like it has had a tuneup!! Like I said, I'm a believer! It was "just" Gold GC too!