Will this diffuser scrape on driveways or steep inclines?

The LCT design extends the lower rear profile, so approach angle will be reduced compared to stock. Verify ground clearance on your typical routes before installation. If you frequently encounter steep driveways, test-fit or check clearance with the vehicle at normal ride height.

Does this diffuser add functional downforce or is it cosmetic?

This is a styling diffuser designed to complement the LCT aesthetic. Functional aerodynamic benefit is minimal at street speeds. Install it for the visual upgrade and profile line; do not expect measurable performance gains.

What prep work does FRP need before painting?

Sand and prep the surface according to your chosen finish system—whether single-stage paint, base/clear, or powder coat. Follow your paint supplier's surface prep guidelines for adhesion and durability. Do not apply finish directly over the as-molded surface.