Will this diffuser scrape on steep driveways or inclines?

Rear diffusers sit lower than most bumper covers, so approach angle matters. Before installation, measure your current bumper's ground clearance on your driveway's steepest point. The diffuser will extend slightly lower—verify clearance at that angle to confirm your driving environment.

Is this purely cosmetic or does it generate real downforce?

This is STI-style visual aero. The profile mimics factory diffuser geometry, which is tuned for underbody flow management rather than high-downforce track conditions. For street driving, the visual impact is primary; any aerodynamic benefit is secondary and incremental.

What finish should I apply to the carbon fiber?

The weave arrives sealed and ready for your chosen finish. Sand the surface lightly and apply UV-protective clear coat to prevent oxidation and maintain the carbon's depth. Custom paint is also an option—prep the surface before application per your paint product's instructions.