Replace the AUX input to fix noise quality?

It's not your head unit - it is the highly compressed and limited sound quality that your phone provides.

The sound tracks on CDs are full range and not compressed as the has a very large storage capacity. However, in order to be able to cram lots of different soundtracks over over cell phone networks, they limit the audio range and use heavy compression on those soundtracks - and you are hearing the difference.

There are different degrees of compression in common use. Cell phones are at one extreme, while the surround soundtracks on movie BluRay discs are at the other.

PS: Your heading mentioned Noise on the Aux input: If this is your problem, it might well be an issue with ground loops - particularly if you are using a charger on the phone when listening to the phone. If that is the case, you can purchase a ground loop isolator from Radio Shack to isolate the phone's ground from the car.

 

You are probably covered under T-SB-0067-08.
Applicability has been updated to include 2008 model year 4Runner, Prius, RAV4, and Solara.
Some customers may notice noise in the auxiliary mode of their audio system when using an MP3
player or other external audio source connected to the 12V power port of the vehicle. An improved
auxiliary port and in-line filter has been developed to improve this condition.
Get it replaced for free at your dealer. I had it done on my 2007 and heard a significant improvement.

 

save yourself time,, and money, and you dont have to take a chance with a dealer getting into your billfold with some scam
try this! worked great for me,

 

Guys,
The OP has never bothered to respond. We really don't know what his problem is.