A long time ago, Bentleys were racing cars. In 1930, a Bentley won the Le Mans 24-hour endurance race for the fifth time, roaring along at 130 miles an hour and overtaking a Mercedes to claim victory. The next year, Bentley was absorbed by Rolls-Royce, which eventually made the Bentley into a Rolls with a different grille. But the memory of those distant glory years never faded, and a few years ago Bentley began reaching for its own identity as a sort of Rolls sports sedan.