"My Daily Driver requires premium, so don't want the Mustang to also require Premium."
This is baffling to me.
I understand avoiding the overall cost of the tuner, but doesn't the daily see all the miles and the fun car get uses sparingly. Whats an extra $10 a month for the fun car. maybe get a DD that uses regular. Maybe get a tuner for your DD that would detune to use regular!
My DD requires mid grade minimum and the Stang is in premium only.
I don't own a snow shovel.