In reply to estivoautumnal:
Should be fine.
I am on a MacPro but older with dual 2.8GHz Quad-cores, and 12 Gig of RAM. Not sure about the video card but I doubt that will be the problem.
I would upgrade to OSX Mavericks since it seems no slower, and is a better system. By far the most painless new Apple OS upgrade in recent years.
Live rendering can be slow but it is much better than the old FCP 7 or 8 or whatever it was.
Alan