Does anyone happen to know which are the best flowing backboxes for the newage impreza? Some fairly easy physics leads me to believe that louder backboxes probably provide better gasflow than quieter ones but i was just wondering if anyone knew more definitively.

The main reason for the question is i'm thinking about changing the Prodrive box i've got for something else but I don't really see the point if it's not going to help in some way.

 

The quieter boxes have more sound deadening in and have a larger silencer. As far as back box only, I'd be looking at how loud I want it to be and budget to be honest mate