Truthfully the only reason you may need 0W-30 in that car is if you live in colder climates (freezing temps). 5W-40 should be fine for warmer climates or summer driving.

Keep in mind also that you are introducing extra pressure into your oiling system. Not severe, but some. You may also see your mileage go down ever so slightly as a heavier weight oil will induce some drag on the engine's reciprocating components.

Hope that helps.