Can I buy any PS3?

Hi guys,

I'm going to buy a PS3 as it can play games from an external hard drive.

I was just going to get the 12GB slim PS3. My question is, are all PS3 versions able to be modded to play from external hard drive? And are all versions supported, so when I get my PS3 can I update to latest version and then mod it to play from external hard drive?

I also have really scratched games from when I used to have a PS3 before, they are likely unreadable. If I get an iso for it can I just extract that iso onto the hard drive?

Thank you so much.

Sam Wharfe