Owners of past Mitsubishi Diamantes may not recognize the new model, which has smoother styling and more power. It doesn't even feel like the old Diamante, which was generally ignored. Many automakers are trying to keep base prices of their ``near-luxury'' market cars just under $30,000. The top-line LS version of the new, Australian-built Diamante I drove comes in just under the wire at $29,990. A base ES version with less equipment arrives in February, probably at about $26,000. The 1996 Diamante more or less took a year off, being available only to rental car companies. While decent, previous Diamante sedans were far from special. The more-refined 1997 model has been worth the wait, and can take on rivals such as the $29,900 Lexus ES 300 and $29,995 Cadillac Catera. Never mind that the Mitsubishi nameplate isn't as illustrious as the Caddy or Lexus nameplates. The swift, highly aerodynamic new Diamante LS I drove is plenty luxurious, and has virtually no wind, road or engine noise. The new Diamante four-door has the same 107.1-inch wheelbase of its predecessor but is about four inches longer and higher. Thanks to the sleeker interior's larger dimensions, tall rear-seat passengers no longer feel squeezed--although long-legged ones still might want another inch or so of legroom. Greater use of aluminum gives the solid new Diamante more chassis rigidity and trims weight by several hundred pounds. That reduction and a lighter, smaller 210-horsepower V-6 result in lively acceleration--0 to 60 m.p.h. in 8.3 seconds. The overhead-camshaft, 3.5-liter, 24-valve V-6 is far more potent than the old 172 horsepower engine. But my test car's smooth four-speed automatic transmission occasionally didn't downshift quickly enough for good passing times on highways. It felt as if the transmission's adaptive control management system was screwed up. A revised suspension that easily soaks up bumps gives the Diamante better handling and makes it more fun to drive, although it's more of a luxury sedan than a sport sedan. The Diamante LS definitely is worth a look.