Motown's dapper gents changed with the times after the '60s, evolving well beyond the snappy harmonies and gushing romance of their early hits. “Feel Free,” from 1976, is a slinky funk odyssey worthy of Marvin Gaye, while the following year's “The Show Must Go On” commands a marathon disco groove. The veteran quartet even nailed synth-pop empowerment on 1988's fist-pumping “Indestructible.”