The solution like that can't be for newbies. It's not like you install some script, click the "GO" button and it synchronizes with your current members on the fly. I doubt it would be possible to implement in any script.

I have experience with miniBB installing it over my customers websites as the forums attachment to their presentations, and so far they all are happy. I did synchronization once, but it was really simple because customers website's login was a simple routine. If there is something difficult on your website, you may better contact this forum software authors. Their support fees are very modest.