Will this diffuser scrape on steep driveways or inclines?

The diffuser extends minimally beyond the OEM bumper profile. For steep approach angles, measure the rear bumper height on your vehicle before installation. If you frequently encounter steep inclines, verify clearance with a test fit.

Is this purely cosmetic or does it add functional downforce?

The integrated vane design provides visual aerodynamic detail and modest air direction at the rear. For measurable downforce, this works best as part of a complete aero package rather than as a standalone upgrade.

What preparation does the FRP require before painting?

Sand and prep the surface according to your chosen paint system's requirements. Most painters recommend a light scuff and primer application before topcoat. Consult your paint supplier for specific grit and primer recommendations based on your finish.