Will this diffuser scrape on steep driveways or inclines?

The Heaves profile is designed to follow the factory bumper line with minimal extension. Measure your current ground clearance at the rear bumper corner — the diffuser adds modest projection. If you regularly bottom out at steep angles, verify clearance on your specific setup before finalizing installation.

Does this diffuser provide functional downforce or is it cosmetic?

This is a visual enhancement styled to match the Heaves aesthetic. Any aerodynamic benefit is secondary to appearance. It's built to look aggressive without the complexity or cost of a fully engineered aero panel.

What surface prep do I need before painting?

Sand and prep the surface with standard automotive preparation before applying your chosen finish. Scuff the panel to accept primer or base coat evenly. Follow your paint supplier's prep guidelines for adhesion.