You seem to have a pretty good handle on this, but with all due respect I think you may be going about this the wrong way. Your time is precious and should be spent doing more productive things, step back a little and take a look at the bigger picture...

Your company are paying them (probably a substantial amount) for their service and they have supplied this documentation to you. It is not unreasonable to ask them to supply the reasons why you should implement their suggestions and ask them to back it up with the relavant Microsoft technical articles and baselines that prove their statements are indeed correct.

Of course they will not be able to do this, then you can step in with collated advice from this thread as your counter argument. Definitely list this MS technical article in your arguement - http://technet.microsoft.com/en-us/magazine/2008.08.database.aspx

We've all been there and unfortunately sometime it becomes more of a political argument than a technical one at times. Companies tend to favour external knowledge rather than internal purely because they pay more for it.

Good luck!