Does this come with mounting hardware?

The louver assembly includes the slat structure and brackets. Confirm your vehicle's factory mounting hardware is present and in serviceable condition before installation.

Will I still be able to see out the rear window?

Yes. The horizontal slat design has gaps that allow sight lines through to the rear. You're trading some transparency for the louver aesthetic, but visibility is functional.

Does this need paint before I install it?

The louver ships ready to bolt on as-is. If you want it color-matched to your car, prep and paint it before installation—finish any exposed edges or unpainted surfaces before the final install.