Originally Posted by glider

M1 V Twin Is all I use in the motor. It's readily available and is widely used in hi dollar new cars too. It also says to use the M1 for oil changes in the same cars on the cap so there must be more to it than just a low supplier price IMO, plus I've never seen Amsoil touted as the factory fill in anything.

These cars all use it as a factory fill (M1)

Aston Martin
Bentley Amage and Bentley GT
BMW all models
Cadillac CTS, XLR, SRX and STS
Mitsubishi EVO
Porsche vehicles
Chevrolet Corvette
Dodge Viper
Mercedes-Benz AMG vehicles
Mercedes SLR
Pontiac GTO
CVO Harleys