Conclusion: This was the final addition to my van sound system. I installed all RF speakers in my van (7 total) including bass. My van rocks. The sound is so clean, clear, and crisp I'm hearing parts of music I never even herd before.
Summary: Replacement for factory 6x9 front door speakers in a '16 4Runner. Big improvement. There is still some residual boominess, but that could be from the factory speakers in the rear doors. Very worthwhile upgrade.