Visual enhancements include a more aggressive front fascia and model-specific 18-inch wheels.
The Coupe model gets a much more assertive rear wing than the comparatively modest lip spoiler on the four-door Sedan Si.
The Civic Si will be tasked with taking on cars like Volkswagen's GTI, Ford's Focus ST and even Hyundai's Elantra Sport.
The Si Coupe retains the same racy, teardrop shape as standard Civics.
It'll be interesting to see if the Coupe's big wing negatively affects rearward visibility.
Honda hasn't disclosed pricing yet, except to say that the new Si will start in the mid-$20,000 range.
Like the standard Civic Sedan, the Si four-door gives up little of the Coupe's rakish looks in exchange for the added practicality of four doors.
The new Civic Si features adaptive dampers, a two-setting drive mode switch and variable-ratio electric power steering.
Standard equipment levels include a 7-inch touchscreen audio system featuring 450 watts of power, along with Android Auto and Apple CarPlay compatibility.
Civic Si seats are known as much for their grippy bolsters as their red stitching, and this new generation appears to keep the tradition intact.
A six-speed manual transmission is standard equipment.