Well after what was probably about 2hrs, firefox finally finished building. The build itself actually went very smoothly, as I managed to find a set of instructions online here. Basically just followed the instructions closely and all went smoothly. Somethings to be aware of are, that I had minor problems with, were my computer going to sleep about half an hour in and having to restart the build which sorta sucked. Also on the instruction list it says 1gb disk space, but in reality (at least for me) it ended up being 2.4gb's.
One thing I found sort of odd tho, was the fact that I couldn't open minefield and my already existing version of firefox at the same time. If i tried opening one while the other was open, it would just open another instance of the one that was currently open. Sorta odd but w/e.