The Lexus GS 450h’s EPA estimated fuel rating is 25 city and 28 highway, but you’ll probably get closer to the low 20s in combined driving. Our test featured zero city driving, so your mileage will certainly vary – but that’s our educated guess on actual mileage numbers. That’s really not the point of this car, however – it’s all about power, baby, with more fuel efficiency and better emissions than one expects to get with this kind of performance.