We know you have an opinion on how things should be run around here. These are suggestions for the forums, and the website.This forum is not a place to ask for suggestions to your own coding (or otherwise) problems.
I dunno, I really like phpbb and I really don't notice any speed issues with it. It might be a tiny bit better, but not worth all the trouble of changing over.
Speed issues were taken care of when the forums were moved to another server that isn't hit as much. The good people at ImHosted were good enough to practically put us on our own server (basically, a higher powered server with only a few sites on it) in exchange for their banners on the page. Since the bandwidth is high on this site and PHPComplete, this is good for us.