Filed under: Portable AudioThe natural successor to the TUA-T500HD does more than just enable a slew of HD Radio-ready Alpine head units to tune into HD Radio, as it throws in that recently unveiled iTunes tagging feature for good measure. Hailed as "one of the first in-car applications combining HD Radio with iTunes tagging," this accessory will team up with Alpine's latest lineup of in-dash players to let users bookmark over-the-air tracks for purchase at a later time, effectively eliminating the "Now what was that song?" syndrome. Sadly, we've yet to see a definitive price or release date, but you can rest assured that the TUA-T550HD is on the way.