This is my fifth Lexus and my third GS 300. I have owned several luxury cars (Mercedes, BMW, Volvo) and none compare to the quality and lack of problems and issues to the Lexus line. I prefer the rear wheel drive and thus continue to choose the GS 300. The 6 cylinder engine is more than sufficient to create power when needed. The 400 is simply a waste of money. The car is quiet, comfortable, sporty and a joy to drive.