After seeing a side profile of the BRANEW aero kit for the Lexus IS-F, I had to find more photos. Now, I suspect it has more to do with the dropped suspension, but this kit almost settles the exterior design down:
More than anything, the reworked side-steps minimize the visual impact of the fender vents, which reduces the front-heavy look of the IS-F. Not a big fan of the rear bumper mod, though.
[Source: BRANEW]