One of the bigger challenges facing automakers in recent years has been making usable and safe interfaces for navigation, stereo, and hands-free phone systems. With the 2014 RLX, Acura shows off its latest attempt at tackling the interface challenge, but ends up with a kludgey design that will leave drivers frustrated. The RLX replaces the company's RL model as its flagship sedan, and incorporates enough changes to warrant a different model name. It successfully ups Acura's luxury quotient through the use of more quality interior materials and new technologies, yet still does not quite feel up to the big luxury of a Mercedes-Benz S-class or a Lexus LS 460. However, it is not as pricey as those models, either, putting it in a near-luxury class with new contenders such as the Kia Cadenza. Per Acura marketing strategy, the RLX does not have factory options so much as different trim levels. This new model can be had in a base trim or with a succession of packages, each adding features to the previous. The first upgrade adds navigation and the next brings in various technology features. An amazing Krell audio system comes in at the next level, and the top package, which the car I reviewed had, adds advanced driver assistance features.