Should be fine. Just heat up the motor a tiny bit before starting them you also need to tune the motor more rich when its colder. With my Vehicles. (MGT and ST-1) I leave them in the garage and just start them without preheating, but preheating is alot safer and it takes forever to warm up the motor in -20C from my experience
Also you will find the vehicle won't be as durable since plastics are more brittle in the cold.