I mix 1Q RL with dino oil (G2 or G3) to get the benefits of POE's. I had used M1 on two vehicles purchased new and after 67k miles one, 90k other, started the RL blend. This oil change appeared to have dramtically cleaned the engines. Other than than M1 EP for longer OCI, the syn's aren't worth paying much of a premium. If you can find RL near you, your total cost can be equal to typical syn OC.