Upgrading the PS3 40 GB model??

[jcbigredfan]

Good afternoon all:
How big can you upgrade the hard drive on this PS3 40GB? I own an PS2 already and should not have to buy the 80 GB model at all?? Just buy the ps3 40 GB and save the $100....save for movies or something else.. One other thing like the connections for HDMI 1.3 ... are the same for both models, not missing anything else I think???? Thanks for any input.