Can you knock the baffles out of the stock can and still have same performance just louder?

 

If you knock the baffles out you will change the airflow, which will effect your performance. Not quite sure why you need it louder but whether you knock them out or buy aftermarket it will be best to remap it for the change in performance. Enjoy the ride.

Welcome to KF!

 

loose some weight with a slip on if you must. But a tune is nice afterwards but not always mandatory. Good luck and welcome to KF.