2 questions for my C6 Z06 (parts to buy)

[Blu427]

I decided 2 years ago that I needed a backup camera in my C6Z.
I had always been disappointed in the sound quality of the head unit, but as
mentioned earlier the engine purr was all that mattered.
I installed a Sony head AX5500 to get the camera, but was amazed how it
improved the sound quality using the same speakers.
I purchased it from Crutchfield who I highly recommend. They suppy a complete
master install manual and a list of all components required. I installed in a couple of hours.
I saved the original head unit for a future enthusiast to re-install when they want originality.

 

[audi911]

So I ended up buying an FM transmitter,
It works well but when I crank up the volume it becomes static and pops (everytime there is some kind of bass)
I bought this one from Amazon
FM Transmitter

I'm thinking about buying another one and trying it to see if a different model is better, but I'm wondering if this is just a limitation of what these kinds of transmitters can do?