Friend staying with me in CO has a Mazda Speed 3 and left it outside over night when the temp got down to about 10F, maybe lower. We got in early this AM to hit the gym and the car started right up, no fuss and no unusual engine noise what so ever. Dash read 7F at start up. The car felt and sounded as smooth as the 0w40 in my Alti SER during similar starts and RLI 5w40 in my Speed 6. Friend says hes started in much colder temps at the ski resorts, likely -10F often and no issues even then. He's been running the M1 15w50 since about 3K miles. Impressive to me.