Will this diffuser scrape on driveways or steep inclines?

Rear diffusers sit close to the bumper line and may contact steep approaches or heavily angled driveways. Before committing to installation, measure your current rear bumper clearance on your driveway. If you already bottom out the factory bumper, this diffuser will have the same behavior.

Is this diffuser functional or purely cosmetic?

Forge-style diffusers are designed primarily for visual impact. They create the appearance of aerodynamic function through styling lines and fins. For measurable downforce at street speeds, a larger, ducted diffuser would be required — this is a styling piece.

What do I need to do before painting?

Sand and prep the surface with your chosen sandpaper grit before applying primer and topcoat. Ensure all mold lines are smooth and any dust is removed before finishing. Follow your paint system's surface prep guidelines for best adhesion.