Will these fit my factory bumper, or do I need the N1 RC bumper first?

These vents are designed for N1 and N1 RC-style bumpers only. If you're running the factory bumper, verify that your bumper has the corresponding N1-style mounting holes before ordering. Check your bumper's vent opening diameter and hole spacing against the vent footprint.

Do I need to drill or modify my bumper to install these?

No. These vents mount to factory N1-style hole locations without modification. Line up the mounting points, secure with appropriate fasteners (reference your vehicle service manual for sizing), and you're set. If your bumper lacks the pre-drilled holes, you'll need to drill them yourself — measure carefully before starting.

What prep work is needed before painting?

Sand the surface to your chosen grit and clean off all dust. Follow your paint manufacturer's prep recommendations for adhesion. Since these are FRP, confirm compatibility with your primer and topcoat system — some shops recommend a flex additive for plastic-to-paint bonding.