Lexus established some decidedly lofty benchmarks when it set out to create the world's first hybrid luxury sport sedan. Beyond a suitably generous load of comfort and convenience features, this rear-drive mid-size four-door was charged with providing the performance of a vehicle with a 4.5-liter V8 engine while turning out 80 percent lower emissions, operating ultra-quietly in full-electric mode, delivering all the expected levels of luxury and still possessing the requisite amount of enthusiast-grade handling behavior. Launched as a 2007 model and given a slight freshening in 2008, the 2009 GS 450h does a first-class job of meeting all of those criteria with few compromises. While owning its specific sub-segment outright, the GS 450h also faces off against many of the same players as its GS 460 kin, namely up-line versions of the Audi A6, BMW 5 Series, Infiniti M and Mercedes-Benz E-Class.