I have one suggestion and it's one of the reasons why myself and a few others are buying vBulletin, rather then IPB. You currently have 2 core version to best fit a 3rd party optimizer. You should encode IPB to work as a stand alone and not have to reply on a 3rd party.

That's for the demo version. The full version you buy is not encoded at all. vBulletin doesn't even offer a downloadable demo... And you cannot safely encode a script without the use of a PHP extension, either Zend or IonCube. If it's in pure PHP, it can be decoded very easily.