If your looking for a certain sound or look then whatever it takes is the thing you need. On the other hand if someone is forking out the bucks to put a 5" on with the hopes of gleaning more power out of his EZ then he is going to be disappointed with the results of his expenditure. While this seems obvious to those steeped in the lore the new guys on the scene are not necessarily going to be aware of all the things that constitute the conventional wisdom of bombing a cummins. It is a wonderful thing to have so much collected wisdom in one accessible place.