I just came over a rather small and insignificant tweak that could help the boards, probably only save a few megabytes bandwidth a month but it all adds up right? Anyway, when you go to edit a post it displays the "Quick Reply" form at the bottom which I would deem a rather unnecessary function because you only came to the page to edit a post. Im not sure what sort of savings are but I would think its worth it for a board of this size.
It displays it only because it was there when you started. The edit function is AJAX, so the quick reply area is not retransmitted, it's left over from before you hit the edit button. If you right click the edit button and open it in a new window, it will use the old-school (non-AJAX) style edit, which requires a full page reload and as you can see there, it quick reply isn't there. Long story short, is no, it wouldn't save any bandwidth because when you edit a post, it's not sent from the server.