A small crossover aimed at Gen-X and Gen-Y customers, who will soon make up as much as 80% of entry-level luxury car buyers, the Infiniti QX30 is an important model for Infiniti. The QX30, and the related Q30 hatchback, were developed in concert with Mercedes-Benz, and the cars share their overall architecture with the Mercedes GLA, CLA, and current-model A-class. Despite the sharing of hardware and similar target customers, the cars really don’t look or feel related. Mercedes’ traditional...