Will this diffuser scrape on steep driveways or inclines?

The Taveran diffuser extends minimally below the OEM bumper line. Check your current bumper clearance on driveways and low-angle ramps—if your stock bumper clears, this diffuser will behave the same way. If you frequently bottom out on stock geometry, this will not change that.

Does this provide functional downforce or is it cosmetic?

This is a styling piece designed to complement the Taveran rear bumper aesthetic. While diffuser shapes do manage airflow, this diffuser's primary purpose is visual integration with the 911 platform. Do not purchase this expecting measurable downforce gains at street speeds.

What finish should I apply before installing?

Carbon fiber can be left in its natural weave or clear-coated for UV protection and durability. If you choose to paint, sand and prep the surface thoroughly before applying your chosen finish. Many owners prefer clear coat only to showcase the carbon weave texture.