Since 9001 doesn't really define anything in terms of requirements you'll probably want to spend some time putting together what it is your organization wants to do with this content. Does your organization need/want a content management system? You're referencing revisioning on documents, so I'm guessing yes. Is this going to be a one off for the engineering/manufacturing folks? You could so something like this in subversion and have reasonably simple versioning of your documents. A wiki model works if you're just trying to do knowledge capture but I'm guessing you've got structured documents you need to manage. If you've got people who are fairly technical and can handle the caveats that come with something like that it's cheap and easy. However, these types of implementations frequently turn into folks in marketing or somewhere else saying "well we have FOO over in engineering we can probably use it too", next thing you know you've got the whole company using something that was kind of cobbled together for one group. Sounds like you've already got SharePoint, it's usable but I'm not a big fan of it as a content management system. Works decently as a collaboration platform. I haven't seen their latest stuff and I know they're trying to make moves in that direction so it might be better, but at last view I was underwhelmed. It's very platform specific, the search functionality was poor, it was difficult or impossible to get a good metadata model together and security was goofy.
Try and look towards the future and see if your organization is going to need to take it up a notch in their content management needs. How complex is your security model going to be? How much content are you expecting to manage? Are you going to want a full text search capable system or would a metadata search be good enough? Think about a metadata model for your organization, then research the topic and rethink it. A good or bad metadata model can completely change the fate of a content management system implementation.
What I've seen of Alfresco I like, it's free software so if you're budget constrained or just value that type of thing you've got that going for you. Someone else mentioned Knowledge Tree for a FOSS product, I haven't touched that so I can't comment. If you're going to go commercial I really think Oracle has a great product with their UCM platform (used to work there), but it's gotten god awful expensive and they suck as a company to deal with. Documentum seems like a massive resource hog and maintenance intensive from what I've discussed with people who've done work with it. I had an install of TRIM under my care at a previous gig, HP owns them now, and that had some quirks but was generally good. If you're focusing on records management capabilities this probably deserves a closer look as that's what they kinda specialize in. OpenText is pretty highly regarded, but I haven't touched it or known anyone directly who has.