Optimizing MPG in the Winter

[DrumAce]

Hello friends,
I park my 22 ST in an insulated garage but I live in Canada so winter is cold. I use 91 octane fuel.
Questions:
1. The manual says the car is ready for driving as soon as you start the engine. Is that actually the case, or should I let the engine run for X minutes before I go?
2. If I have a stop for a few minutes in a cold weather, does it make more sense to turn the engine off (and then it cools down dramatically and might take more fuel the next time I start the engine), or to let it run while the car is parked (e.g., when picking up the kids from school, a typical few minutes stop)?
3. Does using a higher octane helps getting better MPG in cold weather?
4. Does slippery mode consumes more fuel than ECO?

Thank you

 

[BrooseDaMoose]

1. With todays engines, there really is no need to let it warm up. However, I am old school and always wait 15-20 seconds to let the oil cirrculate for a bit.
2. This depends on how long a "few minutes" actually is. I arrive at my daughters school at 2:00 and she gets out at 2:20. I shut off my vehicle while I'm waiting for her and start it as soon as I hear the dismissal bell ring.
3. Yes, my experience has been that I get better gas mileage when using 91 or 93. But, depending on the cost difference, it may not be worth it.
4. I don't believe Slippery Mode would consume a significant difference of fuel.