I also own a mid-2009 Mac Book and I managed to upgrade its RAM to 4GB (2 x 2GB) and to replace its HDD with an SSD. The next step I would like to make is to upgrade its RAM to 8GB (2 x 4GB), but when I write this message (in 2016) I cannot find DDR2 RAM’s any longer, leaving apart that they are fairly expensive. I would also like to replace its processor with a stronger one, say an Intel i3, i5 or even i7. Does anyone know if its motherboard supports such processors or where can I check this? Thank you in advance.