Will this diffuser clear the road on inclines or driveways?

Diffuser geometry sits close to the bumper line and will engage steep grades and sharp driveway transitions. Verify bumper-to-ground clearance on your setup before committing to installation. Approach angles matter — take driveways slower if you run lowered suspension.

Is this purely cosmetic or does it serve a functional aero purpose?

The aero look profile is styled for visual presence. While diffuser design has aerodynamic roots, real downforce benefit depends on speed, suspension setup, and overall body geometry. Buy it because you like how it looks — that's where the real value is.

What prep work do I need before painting?

Sand and prep the FRP surface per your paint system's requirements before applying primer and color. Work with your chosen paint supplier or shop to confirm surface prep specs — different primers and topcoats have different demands. The diffuser ships ready for that process.