Should I do straight pipe?
 

I just bought an 2016 a6 and I want it to make some noise. I don't want it to interfere with the warranty and need info on whether straight pipe would hurt the engine in any way. You guys have any suggestions?

Straight pipe will for sure get your warranty voided once they look at anything exhaust / emission related.
Next thing to worry about is error codes. Unless you got some top-notch foulers/tuning your Audi will start throwing codes - either scenario will void your warranty as well.

I would not go for the straight pipe unless you tune and get out of warranty.

Engine wise it will not hurt it though.