Will this diffuser scrape on driveway inclines or speed bumps?

The Z1 Speed diffuser is designed with minimal downward extension to work with lowered and stock suspension setups. Review the profile against your vehicle's current ride height and ground clearance. If you run significant lowering, test approach angles with ramps before committing to permanent mounting.

Does the diffuser include mounting hardware?

The diffuser assembly is supplied as a bare panel. Verify your existing rear bumper mounting points and hardware before ordering. You may reuse factory fasteners or upgrade to stainless hardware depending on your installation method.

Is this purely cosmetic or does it actually improve airflow?

The Z1 Speed design features functional vane geometry that channels rear-axle airflow and reduces turbulence at speed. On track, this translates to marginal downforce gains. Street use will see aerodynamic benefit but minimal performance impact unless you're running high speed regularly.