You can quite easily edit the look and feel of UBB 6+ with its Templates... It's quite easy to accomplish too

And along with the numerous bugfixes added since UBB 5, it really is better to upgrade to (a) Cut down on the amount of hacking you'll have to do, as Charles said, and (b) To make sure your board is as secure as possible. It's well worth the effort, trust me.
Oh, and by the way, it looks like the lease on your domain name is about to run out...
