I don't think that any Sports talk FM stations need to be in HD, but a local station is, KRLD 105.3 The Fan, in Dallas. While other HD stations in Dallas can get their timing transfer from analog to digital correct, KRLD just doesn't give a rip, and so, when I tune to them in the car, the HD signal ALWAYS repeats a few seconds of what I just heard on the analog signal.
My JVC KD-HDR1 receiver tunes to the analog signal, and then switches to the HD signal. Smart broadcasters fine tune their HD signals delay, so that there is no "repeat" of what you would have just heard on analog. KRLD is one of the few broadcasters that insist on broadcasting in HD for their AM 1080 signal. That AM HD signal's quality is grating, and I cannot listen to it in HD.
The main format that I truly appreciate an HD signal for is Classical music. For those really quiet soft parts of symphonies, that is the place where the HD signal shines. But the local city-owned station, that used to broadcast in HD, no longer does. I contacted them about using other HD sub-channels to broadcast film and soundtrack music, other than the "Greatest Hits" of film, which they regurgitate regularly. But, my request fall on deaf City of Dallas ears. Only playing the greatest hits keeps the "Dallas is Superficial" moniker alive and well.
The biggest use I have of HD in the car is to listen to AM signals on FM HD sub-stations, as the AM channels have their own dedicated band of presets, and so it's easier to stay one FM band of presets, and listen to both AM and FM signals.
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When I buy a new car, HD --WILL NOT-- be a requirement, but Bluetooth will.