I have a 2010 4runner SR5. Last year I replaced front and hatch speakers, installed an amp and subwoofer. I left the factory radio and used the speaker line as input to the amp. I am satisfied with the result. I hesitate to replace the head unit with aftermarket because I am not sure how much the sound quality can be improved that the cost can be justified. The other reason is that I like the current appearance with the big knobs.

Recently I feel like I need a backup camera. A lot of time I am worried while in the places like church with children around. One option is adding a rearview mirror with the camera display, but I prefer a larger screen on aftermarket head unit if the sound quality can be improved noticeably at the same time.

I know some members in this forum have gone through similar route, please advise me with your experience. Thanks in advance for the help!

I actually installed a new headunit before installing new speakers. The new stereo makes the speakers sound at least 3x better. If you want your audio to sound great, I would advise it.