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.
