The Lexus IS 250 and IS 350 are by far the oldest designs in this class, and they enter a seventh model year essentially unchanged. As it is, the 2013 IS lineup shows its age the most inside, while what was at its original launch a somewhat conservative exterior has stood the test of time very well.
The exterior of the two IS sedans, which is virtually the same whether you go with the IS 250 or IS 350, somehow manages to look contemporary, fresh, and handsome, combining a sleek, low, and attractive silhouette with a hoodline that's a bit lower than most other recent designs, plus a gently rising beltline--giving it a pleasant, wedge-like look from some angles, and an undeniably sportier, more aggressive look than the comfort-oriented ES 350.
In recent model years Lexus has also kept the exterior updated by giving it new exhaust tips, along with HID headlamps and LED running lamps in the IS 350. An F-Sport Package gives the IS an even more serious performance look.
With a relatively tight cockpit-like layout, a rather wide center console, and smooth, continuous dash surfaces, the IS models arguably show their age the most inside--even though trims and materials remain quite good.
IS C convertible models are closely related to the IS Sedans--not just mechanically, but design-wise--and they carry over with essentially the same front-end design, as well as a rear design that's only a little taller and more bulbous. Side sheetmetal is a little taller and more slab-sided in convertibles.