That’s fair enough mate, still fairly new to me too.
Like I’ve said I am sure some more experienced people will offer guidance after me so await their views too but my 2p’s worth….
You have a few options;
Full cat back
X-pipe replacement for centre resonators
Back box change or removal.
If you have deep pockets I am sure many will suggest full cat back AWE or similar system.
If it’s just sound improvement you’re after many go for the x-pipe to add a deeper and better exhaust sound.
I have personally removed the back boxes on my S5 B8 which is loud but not unbearable in my opinion. Plus I know some ‘friendly’ MOT testers 😉
The choice will depend on what you want to achieve and how deep your pockets are.
But as I have said please await more experienced and knowledgeable people as I’m still finding my Audi feet.