The 2015 Lexus RX is offered in three core models. The RX 350 is powered by a 270-hp 3.5L V6, while the RX 450h has a 3.5L V6 and a version of Toyota's Hybrid Synergy Drive system. The third model in the lineup is the RX F Sport, a special non-hybrid performance model. Engine output is the same in the RX F Sport as for the RX 350, but there are several key differences. The F Sport gets an 8-speed automatic transmission, while RX 350 models have a 6-speed. Furthermore, the F Sport has a special performance-tuned suspension, split-spoke 19-inch wheels, and its own performance-oriented tuning for the stability control system. Appearance-wise, the F Sport is easy to spot, with its mesh-finish grille, black or Cabernet leather interior with silver stitching, ebony bird's-eye maple trim, back headliner and aluminum pedals. Both the RX 350 and the RX450h model lines are offered with a choice between front-wheel drive and all-wheel drive. All-wheel drive RX 350 models have an Active Torque Control system, with an electronic coupling that can send up to 50 percent of drive torque to the rear wheels when needed by traction. Hybrid models with all-wheel drive have a different system, with torque to the rear wheels applied through an independent 50-kilowatt electric motor system. In all 450h hybrids, a front-mounted 116-kilowatt motor-generator system works through a planetary continuously variable transmission, delivering EPA ratings of up to 32 mpg city, 28 highway. Hybrids offer the same cargo and passenger space as the RX 350. The RX is configured for those who put the priority on comfort, and so the cabins are plush, comfortable, and quiet. There's seating for five adults, with supportive bucket seats in front and a full-size bench seat in back. All RX models ride on a front strut-type suspension and double-wishbone rear suspension, which helps keep the ride smooth and handling responsive. That also assures a low cargo-loading floor, and if you fold the 40/20/40-split rear seat sections down as needed you have impressive versatility for combinations of cargo and passengers. You get 40 cubic feet of cargo space with the back seat in use, or around 80 cubic feet with all the rear sections flipped down. The standard sound system on the RX has 12 speakers and includes The Mark Levinson Surround Sound system that's optional on the RX model line is configured for audiophiles and has 15 speakers and 330 watts of power. Standard features on most RX models include 10-way power front seats, a leather-wrapped steering wheel with audio controls, Bluetooth connectivity, voice recognition and customizable vehicle settings. A Luxury Package adds semi-aniline leather, a wood-and-leather-trimmed heated steering wheel, front cushion extenders, an upgraded climate control, a power moonroof and special 19-inch alloy wheels. Meanwhile, other options include ventilated front seats (through a Comfort Package), the Mark Levinson audio system (along with a hard-disc navigation system, the Remote Touch and Voice Command interfaces), an enhanced Bluetooth system with phonebook download and a back-up camera. It also adds Enform with Safety Connect, a system that includes a suite of apps as well as several emergency and concierge services. Another option pairing is Pre-Collision System and Dynamic Cruise Control, which use the same radar system to help prevent collisions and maintain a set following distance.