Will this cap fit flush with the factory dash opening?

Yes. This is a direct replacement designed to match the OEM opening profile. Install without additional trimming or modification needed.

What's the best way to install this — do I need fasteners or adhesive?

Mounting method not specified in the product data. Test-fit the cap first to confirm fitment, then decide between mechanical fasteners (screws or clips) or panel adhesive based on your dash opening design and how snug the fit is.

Can I paint this cap to match a custom color?

The cap comes in black finish ready to install. If you want a custom color, light sanding and automotive paint will adhere to the hard panel surface. Refer to your paint manufacturer's prep requirements for panel materials.