LAS VEGAS — It’s no secret the mere mention of the word “Lexus” connotes luxury. Lesser known, however, is the fact that some Lexus models, while fraught with the usual upscale amenities its owners have come to expect, are also drivers’/enthusiasts’ cars as well. Case in point is the all-new 2013 GS 350 Sport Sedan. Lexus has thrown all its gee whiz technology into a completely redesigned mid-size GS.