I had the 24" for about a year and had to sell it because of life situations but I just won a 20" model on eBay for $122, including keyboard and mouse. Looks like stock components as there is just 2GB of RAM and a 250GB HDD. It will probably ship tomorrow but I want to order some upgrades as I don't want to use it as is. First, I am reading you can only upgrade to 4GB RAM, is this correct? I would love 8GB, I know I had 6GB on my iMac I had previously sold. Second, I want to put in an SSD to replacing the spinning hard drive. I watched a video and it seems like it is a lot of work to switch it out but I am assuming it is worth it. For those of you that have done it, does the SSD make it fly? --- Post Merged, May 7, 2016 --- Oh and a follow-up question real fast, it says El Capitan works on it, should I do it or make go Yosemite or even Mavericks? Which will run the best on it? I want it to me snappy but don't won't to go any lower than Mavericks though.