Will this diffuser scrape on driveway approaches or speed bumps?

The TS1 profile sits low at the rear, so ground clearance depends on your suspension height and approach angle. Measure the lowest point of your current bumper, then compare that to your typical speed bump or driveway lip before final installation.

What prep is needed before painting this diffuser?

Sand the surface with appropriate grit to promote paint adhesion, then wipe clean of dust. Apply your chosen primer and topcoat system per the paint manufacturer's instructions. FRP surfaces bond well to quality automotive paint when properly prepped.

Does this add functional downforce or is it purely cosmetic?

The TS1 diffuser is designed for visual impact and maintains the factory aero aesthetic. While the vane geometry mimics OEM styling, real downforce performance depends on speed, vehicle weight, and your complete aero package. Treat it as a style match to the TS1 look rather than a track performance upgrade.