I'm interested in purchasing the new vBulletin publishing suite, but before I part with my hard earned cash does anyone know how easy it is to extend and add functionality to? I have an idea for a site and the community features already available in vBulletin would be a huge asset/timesaver. There's no point in re-inventing the wheel. However there are a number of ways I would like to differentiate my site, whilst still tapping into the authentication methods etc. of vBulletin. Does anybody know how easy this is to do? I'm profecient enough in creating data driven sites in PHP and with the wordpress way of creating plugins, so hopefully this shouldn't be too big a learning curve but I wondered if anyone had any experience on advice on this. Also is it possible to download a version of vBulletin to install locally without purchasing ( obviously just to test things out like plugin development without but the site live and breaking the license agreement )?