The Four Tops' four bottoms may have become a little wider after 20 years of performing, but their repertoire of classic Motown hits still sounds sleek and up to date.

Looking like a quartet of conventioneers in garish red jackets and white slacks, the Tops attempted some of their famous fancy precision-stepping Saturday night, but were mostly endearingly loose and sloppy. The harmonies also were slightly ragged, but intact, and the audience at the Warner Theater loudly filled in the gaps in each familiar song.

Lead singer Levi Stubbs' voice still has a sexy, gravelly timbre, and he was funny and relaxed as he led the group through a string of Vegas-sized arrangements of instantly memorable hits such as "Bernadette" and "Baby I Need Your Loving."

Tony Award-winning actress-singer Melba Moore was sassy and assured as the opening act, mixing an engaging blend of stage patter, jazz ballads, tunes from her Broadway successes "Purlie" and "Hair," and her disco-tinged hits, such as the current "Love's Comin' At Ya." Moore's stage training was evident -- she needed almost no mike to reach the back rows with her powerhouse voice. Her instrument took on as many colors as her platinum blouse reflected, from a lush whisper to an ear-piercing squeal to a full-bottomed growl.