The new Peak oil 10W30 in 1994 Lexus LS400 with 240k miles improves the gas mileage from normally 17.0-18.8 MPG to 20.2 MPG for the first tank. The engine seems to run quieter and smoother than ever, the car had seen many different brand of oils, from M1 5W30 to Chevron Supreme 10W30. May be because it is much thinner than other xW30 oils. As I said in another post, I got FAR 20 quarts Peak oil and with its performance in the LS400, I would buy it in the future instead of any other brand name dino oil for the same price. If I can get my hand on Peak 5W20, I will buy it without hesitate.