Documentation Store / Wiki

[Kitcardirect]

I'm looking for a solution so I can allow authorised customers (ones that have a specific tag) to view documentation on how to build certain components we sell.  Much like a Lego manual.

Each component we sell has a different manual.

The manual is made up of several hundred pages with thick imagery and is now getting too big for us to produce in a pdf format, hence the need to a wiki type document store.  I want to be able to update individual pages immediately when a customer has a query or something isn't right, I don't want to have to edit a massive pdf, export it, then upload it because this is just too laborious. 

I want this to live behind "my account" so that users have to log into the site first, and then they can gain access to the manuals.

I'm currently looking at FabEXT wiki, which I think will do the job, but I want to make this only accessible to certain authorised individuals.

Can anyone point me in a direction of either custom code or an existing app which will do what I'm looking for.