The cost of the high grade fuel is not a limiting factor in owning the car

if you fill up with premium it will cost a little more but you will not end damaging the engine or engine related components, also you will achieve a better fuel mileage than if running on the low grade fuel.

in the long run it will not be as bad as constantly blowing O2 sensors or even damaging the pistons(which retail for over $1000 a set!)