One problem in using 15k oil changes is the warranty on a new car. If for whatever reason the engine craps out and the dealer asks for oil change records. They may say the customer did not follow the recommended OCI and the warranty is therefore void. Literature from Amsoil may not be much help. And changing AMsoil every 5k would definitely get expensive. The same could be said for M1.
In reality following any routine oil change schedule with a good oil and filter, the engine will last a lot longer than the rest of the car.
Just my opinion. YMMV
In reality following any routine oil change schedule with a good oil and filter, the engine will last a lot longer than the rest of the car.
Just my opinion. YMMV