Unsure if you are looking to change, but I recently switched from stock and was incredibly surprised at the difference disparate pipes make. I guess it says more about the stock pipe than anything as I switch pipes/headers often but this was substancial difference.
Assuming you are looking for an aftermarket, what specifically are you looking for out of a piper? That might help you make a more educated decision. I tried out 2013/2058/053/RE11 pipes, and they were all very different. I decided to run the 053 based on my current setup and how I like to run our Savage.