For those of you who find Britney Spears' everyday oeuvre too cerebral and slow-paced, welcome to B in the Mix, The Remixes. Falling on the spaz continuum between disco Sprockets and a gingko-mad Tae Bo instructor, B in the Mixamps already-aggressive singles like ''Toxic'' and ''Me Against the Music'' to brain-popping levels of synth spiraling, and sad-eyed slow jams like ''Everytime'' and ''Don't Let Me Be the Last to Know'' into Hi-NRG bursts. This party is BYORB (Bring Your Own Red Bull); without it, you might not be able to keep up.

