Hey there, my dad's macbookpro 13" mid 2009 is starting to get slower and slower, therefore he now wants me to replace his HD with an SSD. I looked up the ifixit guide on how to replace the HD which doesn't seem to complicated, also I used crucial's memory adviser tool to find out which SSD would be compatible. Crucial came up with the "Crucial M500 240GB 2.5-inch Internal SSD" but now, after he's done some research of his own, my dad is saying he needs a different one. To be exact the "Crucial M4 2.5-inch". I told him not to buy anything yet and wait for the experts from macrumors to help us out 
Thanks!
Peter
Thanks!
Peter