Lexus RX 450h

The Lexus RX 450h can operate using only electric, only gasoline, or use both in tandem. The 350 uses a conventional 6-speed transmission, but the Lexus RX 450h utilizes a continuously variable transmission.

TheLexus RX 450h hybrid system includes a 288-volt battery pack that sits under the rear seat, which sends power to the front mounted motor-generator that drives the front wheels. In all-wheel drive trims, another motor-generator drives the rear wheels. Both models have another generator that's engine-driven rather than battery-driven, so it functions as a starter and can power the battery pack or other electric motors.

Lexus uses a handling system it calls Vehicle Dynamics Integrated Management (VDIM); it's standard on the Lexus RX 450h and optional on the 350. If the system detects a loss of control, it uses all the electronic systems -- ABS, brake assist, traction control, and stability control -- as well as throttle control to help the RX get back on track. In the 450h, the electronically controlled brakes work with VDIM as well.

Lexus IS 350

Both engines come with variable valve timing for responsiveness as well as fuel efficiency-the IS 250 is quite economical with EPA ratings of up to 21 mpg city and 29 highway. While the IS 250 comes standard with a 6-speed manual transmission, with a 6-speed automatic (and steering-wheel paddle-shifters) optional, all IS 350 models come with the automatic.

In all IS 350 models, a double-wishbone suspension design in front and a multi-link rear setup help reduce weight and increase responsiveness. The suspension in the IS is tuned to be quite firm, yet there's enough give to maintain enough ride comfort for most.

The IS 350 has rather compact exterior proportions, which means that backseat space is tight for the tallest adults, especially in IS C convertibles. However it's quite comfortable in front. Leather upholstery is standard, with new black-metallic accents in the sedan and the IS sedan has a reasonably large trunk.