Regarding Octane requirement, be aware of your altitude. Higher elevations require lower octane numbers to achieve same affect. That's why you always see lower octane numbers at the pump in the Rocky Mountains, for example. The mid-grade offering "at altitude" should yield comparable performance as mid-grade rating at lower elevations.
Keep in mind Octane Rating is primarily an indicator of "anti-knocking" characteristics......or anti-detonation factor. If your motor is not detonating (gurgling sound upon acceleration) then you're probably fine. No need to run higher octane than required for smooth engine. Premium won't make your engine run faster than regular, per se'.
So, don't get all nervous when you see lower octane numbers at the pump in higher elevations (above 3,500 ft or so). It doesn't necessarily mean you'll have any problems. If she does begin to detonate, choose a higher Octane at next opportunity.