Like many middle-aged stars, Sergio Leone's best-known spaghetti Western is getting a face-lift, including an injection of 18 restored minutes. Brimming with compositional style, it features three squinting gun-slingers jockeying for buried treasure in Civil War-era Texas. The pace can drag, but Leone lovers, like Quentin Tarantino, who has called this ''the best-directed film of all time,'' will rejoice. After all, its considerable running time and then-extreme violence made it the ''Kill Bill'' of the '60s. EXTRAS This edition is loaded, but it does shoot a few blanks. Current cast interviews reveal such tidbits as Wallach nearly getting decapitated on set, and on a dubbing featurette we learn that in 2002, Eastwood, then 72, and Wallach, 86, were summoned to add vocals to restored scenes. But the Civil War doc is dryer than Texas sand, and film historian Richard Schickel's commentary lacks the insight that would have come with Eastwood or Wallach riding audio shotgun.