Will this diffuser scrape on driveways or steep inclines?

The Hyper Flow profile adds minimal extension below the factory bumper line. Verify ground clearance on your specific vehicle by checking the lowest point of your current bumper assembly against driveways and ramps you frequent — diffuser extension follows the same geometry.

Is this functional downforce or purely cosmetic?

This is a styling diffuser designed for visual enhancement. It follows the Hyper Flow aesthetic but does not carry performance aero certifications. If you're building a track car, confirm your intended downforce specs with a dedicated aerodynamics specialist.

Do I need hardware to install this, or does it come with bolts?

The diffuser assembly is included; hardware is not specified in the factory package. Source M6 or M8 fasteners (refer to your vehicle's OEM bumper bolt pattern) and stainless steel hardware to match your factory mounting points for corrosion resistance.