This is the most interesting part of the review, and surely what Infiniti execs have been hoping to see...
One of the biggest — and most surprising — differences between the two models is their steering behavior. The all-wheel-drive Q50 S I tested used Infiniti's traditional mechanical steering setup, vastly different from the new Direct Adaptive Steering system on the hybrid: Its electric by-wire architecture uses sensors and signals to steer the car. Although it's standard on top-level hybrid trims or as a pricey option on non-hybrids (starting in a $3,100 package), it's worth it.
The standard system required a heavy amount of driver correction; finding a comfortable center at highway speeds was fatiguing. The overall feel was light and twitchy rather than connected to the road. It seemed at odds with the sedan's sporty mission.
In contrast, the Direct Adaptive Steering system provided a firm, direct feel along with quicker, more responsive reflexes. Despite the vastly different steering systems, both cars exhibited a controlled ride with decent bump isolation, though the S model, with its 19-inch wheels and sport suspension, rode more firmly. Overall, however, the Q50 felt as lithe as its predecessor — confident around corners with impressive grip and little lean.