The actual lens/lamp assembly are the same dimensions as confirmed from my source. The front bumper on the BRZ covers the headlight assembly a bit more, making the eyes look a bit shorter across, and the orange marker light inside seems to be reflected or positioned differently. The front facing turn signals are mounted inside the BRZ headlamp assembly, while the FRS/86 has them outside in the corner of the bumper, above the fog lamps.
The front bumper area also has conservative look on the BRZ, while the FRS/86 has a bit more aggressive and aerodynamically conscious shape with pronounced vertical crease line. The grill of the Subaru is reminiscent of the Impreza with simple low count of thick horizontal bars. The Toyota FRS/86 has the all-new T-logo pattern, which is also used in the meter cluster and center console panel inside the interior.
The rear is almost identical aside from the optional deck wing on the Subaru.
Of course the dimensional difference you see in various lines are from convergence difference in the lenses used to take the two photos.
--Photos from GazooResponse website.
Also at least on released catalog specs at Tokyo show, the BRZ is 10mm taller, probably from the difference in gas charged valving/spring-rates of the suspension.
More obvious is the side garnish atop the trailing front fender, where Toyota/Scion chose to badge with "86 Boxer" emblem (optionally with other garnish choices) the, Subaru BRZ has a simple faux grill...which can be rather cool as well. (I assume these are interchangeable... fun, no?)
[ADMIN Edit: Added more comparison photos.]
