Will this diffuser scrape on driveways or steep inclines?

The diffuser extends below the stock bumper line. Check ground clearance at your parking angles and driveway approach — some owners add a slight protective lip or adjust their entry speed. Measure your current rear overhang before installation to anticipate real-world use.

Does this require cutting the bumper, and is it reversible?

Yes, installation requires cutting of the stock rear bumper. This is permanent. Plan accordingly and ensure you're comfortable with bumper modification before ordering. The diffuser uses the existing holes after trimming.

Is this functional downforce or purely cosmetic?

The RBS design profile adds visual aggression and rear-end definition. At street speeds, aerodynamic benefit is minimal. It's a styling choice first — the aggressive stance and appearance are the primary gains.