What is the best audio system upgrade for an Audi A6?

I recently purchased a used Audi A6 and I am not satisfied with the audio quality. The stock system sounds muffled and lacks bass. What are some aftermarket options for upgrading the audio system without breaking the bank?

I highly recommend upgrading to a Bose audio system. The sound quality is top-notch and it integrates seamlessly with the Audi A6.

You could also consider adding a subwoofer for better bass. I have a friend who did this and it made a huge difference in audio quality.

If you're on a budget, you could try replacing just the speakers with higher quality ones. It won't give you the best sound, but it's a more affordable option.