Considering buying a new 21.5" base iMac. I searched and only found solid information for the 27", but very little for the 21.5" model. I have an Intel 120GB X25-M that I'd like to put in it. I know Apple did some stupid crap with a temperature sensor. Can I add my SSD? If I can't add it, can I simply replace the stock HDD? Are the enough SATA ports? Is there physical space for an additional 2.5" drive? Thanks in advance.