Hi SPS,
You're welcome! There certainly has been a lot of contributions here from everyone (not just myself). We all hope the process of installation gets easier...and I believe with if we foster a helpful but fertile community spirit we will all get there...
OK to answer your questions
:
1) As far as I know at the moment we have to patch the Nvidia cards when we install it the first time. If you are coming from installing OSX from a HD4000 bootup, then yes you have to use Multibeast. But any changes you've made so far, no I don't think with the 10.8.3 it would break it. If anything it should be native by then.
Though I could suggest for stability and speed you could install the Nvidia Mac GeForce driver set, and the CUDA drivers.
2) I don't know about Alfa, but in my experience using 10.8.2 I didn't need to install any USB drivers as USB 3.0 is now running native (as 10.8.2 is for Ivy Bridge) - so I would leave it out - it's been working out fine on my setup so far with no hiccups. Also the Lacie drivers I found before on another setup to have been problematic at times. You probably need them on a 10.8 system, but not on 10.8.2 as far as I know. Also to resolve your USB 3.0 issues you should enable XHCI in BiOS if you can on your system (SET TO AUTO)....heard a lot of problems about that.
3) I've not bothered with the Macbook Update - unlike Alfa I think the Macbook Update is not necessary (for my 560Ti) though not sure for other cards ie. 660/670 etc. But if you have problems you could also add TRIM afterwards with Multibeast or TRIM Enabler (if you so desire). I used TRIM Enabler myself.
4) I use MacPro 3,1 for my definitions. It's worked out for me so far....