i think the HD comment is referring to changing out the old 5400rpm drive for an SSD.

I looked into this and instead went with a 500gb 7200rpm Segate Momentus.

My MBP is one of the older ones (2008 - 2.5Ghz Core 2 Duo, 4Gb Ram, NVidia 8600m GT).

I can run 4 copies quite happily, but 5 seems to lag in places.

i only tend to use my MBP (for wow) when I'm away on business or around friends houses.