Will this interfere with the trunk or hood seal when installed?

No. The air dam sits forward of the fascia line and does not extend rearward into the door or trunk shut line. Clearance is maintained in normal operation and at full suspension compression.

What prep work is needed before painting?

Sand the surface with 220–400 grit sandpaper, wipe clean, and apply your chosen basecoat. FRP accepts automotive urethane and polyester finishes. Follow your paint manufacturer's surface prep recommendations for best adhesion and gloss.

Are fasteners or brackets included, or do I need to source my own?

The air dam arrives as the panel only. Source fasteners to match your vehicle's existing under-bumper bolt pattern and diameter. Most installs use stainless steel hardware to resist corrosion; reference your service manual for the correct fastener specification.