It's not something I'd want to do either, but my hard drive isn't overly full as I've got 3 external hard drives attached, one just for time machine back up, one for ALL my hundreds of photos/video and the third for important documents.Thanks. That is good to know. I have basically the same Mac. 20" early 2009 but with 8gb Ram.
The only other problem I see is that the hard drive is very full. It would be nice to swap it with an SSD but I don't feel very confident opening up the screen!