Will this diffuser scrape on steep driveways or parking lot inclines?

Rear diffusers sit lower than the bumper fascia, so ground clearance depends on your suspension setup and approach angle. Inspect your current ride height before installation, and test the driveway angle that concerns you. If you run lowered suspension, verify clearance with the bump stops compressed.

Does this provide real downforce or is it mainly visual?

Empire-style diffusers are primarily aesthetic—they add visual aggression and help organize airflow at highway speeds, but they don't generate measurable downforce the way a tuned undertray or full aero kit would. The blade geometry complements a track-focused setup but won't replace engineered aerodynamics.

Should I keep the clear coat or sand it off for a raw carbon look?

Clear coat protects the weave from UV fade and oxidation over time, especially in harsh climates. If you prefer raw carbon texture, you can wet-sand the clear coat, but expect the finish to weather faster. Most owners keep the coat on and refresh it annually with UV-protective detailing spray.