I'm looking to upgrade my stock exhaust on my 2016 WRX STi as I want more of that typical boxer rumble, the stock is decent but I think Subaru have notched the sound down a little 

Any recommendations fellas ? I want to keep the same exit styles as I really like the quad pipe finish 

Try fitting unequal length headers first that should give you the lumpy idle etc, failing that try a prodrive back box, had one on my hatch as a dealer PPP upgrade (pre 330s) quad pipe but not too much increase in volume

I thought about the Nameless deletes from the States, however after seeing this video I do like the Borla system. It opens up the volume of the subaru engine wth out the inlet changes suggested.  

 

2015 Subaru WRX STI Borla Exhaust Comparison With Stock Exhaust