Even so, we have a pretty clear glimpse at some significant changes to this GS sedan, including the same staggered, quad-pipe exhaust found on the Lexus IS F. There's also an air diffuser panel nestled between the exhaust outlets, as well as a larger lip spoiler and unique wheels (matching those of the RC coupe) wrapped in high-performance tires.
Last time we heard rumors of the GS F's existence, sources predicted that the M5-fighting sedan would use a tuned version of Lexus' 5.0-liter V8, producing something like 465 horsepower. We have also heard that the automaker plans to reduce weight wherever possible, and that the final curb weight will be something like 3,700 pounds.
Of course, those earlier reports said we'd see the car as early as 2012, and that obviously didn't happen. These days, our spies' best guess is that the GS F will arrive in time for the 2015 model year.