The 2014 Lexus IS begins the third generation of the sports sedan that debuted in 2000. At launch, the IS 350 will be the hottest version available. This trim — with the 3.5-liter V6 making 306 hp and 277 lb-ft of torque — will cost $40,360 when it goes on sale this summer. That’s less than the four-door versions of both the BMW 335i and Mercedes-Benz C350, its main rivals, according to company brass. The 204-hp IS 250 starts at $36,845. Both prices include an $895 destination charge.