"Miami Vice." MCA. Without the overpowering sound-track music, "Miami Vice" would be just another flat cop show--with or without Don Johnson. The ominous textures of Jan Hammer's instrumentals and the shrewdly selected songs by a variety of performers infuse scenes with a riveting tension. On CD, you really feel music's impact--albums and tapes don't do it justice. The crisp, rich digital sound brings a zesty new dimension to such songs as Tina Turner's "Better Be Good to Me" and Glenn Frey's pulsing "Smuggler's Blues" and "You Belong to the City."