Will this diffuser scrape on steep inclines or driveways?

Rear diffusers mount to the bumper cover and sit just behind the rear wheel line. Check your current ride height and driveway approach angle before installation. If you've lowered your suspension significantly, measure the clearance between your rear bumper and the ground at the steepest part of your typical driveway to confirm safe operation.

Does this add functional downforce or is it cosmetic?

This is a styling piece designed to complement aggressive body kits and wheels. Real downforce requires a large, high rear wing or fixed aero elements — a diffuser at stock height won't generate measurable aerodynamic load. Its value is visual: it completes the Velocity aero package look.

What prep work do I need before painting?

Sand and prep the surface with standard automotive prep before applying your chosen base coat and clear. The exact grit and primer type depend on your paint system — follow your paint supplier's recommendations for FRP application to ensure proper adhesion and finish quality.