“Tricky clue,” writes puzzle critic Amy Reynaldo at her website. “Looks like a musical clue, but we’re dealing with the Hyundai Sonata here.” Now that you know that, the answer comes much more easily: CAR KEYS.
This is an example of the masked capital letter, the most devious of all clue tricks in the constructor’s bag. The clue Starters of Sonatas wouldn’t have been as effective, since the capital S of Sonatas gives the game away. Placing the capitalized word at the front of the sentence conceals that it’s a proper noun, as the solver will assume that word is capitalized simply because of its location.
Similarly, the clue Post subject is MANNERS since we mean Emily Post; Nice day is JOUR since it references the French city of Nice; and Boxer who pulls no punches is BARBARA since it’s the senator we’re talking about, not an athlete.