We use 185/60 and I don't think there will be any issues with 75 profile fit. I would recommend against it for 2 reasons: 1) speedo error, 2) it will render spare unusable.
We have a separate thread on tires, but one we have on now and like alot is H rated General RT-43 in 185/60R14. Inexpensive, top 5 rated at TireRack, wildly available, even Walmart has them. They are non-lrr but one of the better rolling non-LRR tire. Max pressure 51psi and from handling point of view 48/42 f/r seems to work the best. The only negative took forever to break in, but it will likely last way past 60k warranty.
If you travel alot at 75mph+ I would look into aero mods. Ecomoddler has information on aerodrag reduction, and MetroMPG posted on his mods take a look.
Edit: Mirage engine seems to have very flexible torque, so I don't believe there is much to be found by taller gearing. At least CVT and 5MT do not differ significantly MPG-wise.
Last edited by cyclopathic; 12-04-2015 at 09:01 AM.
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View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)