I assume the difference is mainly cosmetic and the addition of limited slip on the Circuit Edition?
It seems that the Circut includes, standard, some things available to the core as part of packages, listed below.
In addition to the, arguably, cosmetic differences the Circut will use a Carbon Fiber Reinforced
Plastic roof made using the sheet molding compound process, oftentimes called "forged carbon". This will be lighter, likely lowering the center of gravity and help some with rigidity, which is beyond the purely cosmetic. The same might be said for the additional venting found exclusively on the Circuit. It's likely, but unconfirmed, that the larger wing (and perhaps body molding) of the Circuit will have some aerodynamic +/-. This areo might perhaps offer slightly more down force, but also drag. It dosen't seem that the Circut is any wider in track than the core but they may support wider wheels/tires (or wheels offsets), which could mean opportunity beyond the cosmetic.
- Performance package: Includes front and rear Torsen Limited Slip Differentials (LSD). 4-piston aluminum fixed-caliper disc brakes with red-painted calipers and GR logo; 14-in. x 1.1-in. ventilated and slotted rotors (front), and 2-piston aluminum fixed-caliper disc brakes with red-painted calipers and GR logo; 11.7-in. x 0.7-in. ventilated rotors (rear).
- Technology package: Includes JBL® Premium Audio system with Clar-Fi®, and Qi-compatible wireless smartphone charging.
- Cold Weather Package: Includes heated front seats and heated steering wheel.