Which PS3 model should i am for?

Given that the PS4 is already out i am acquiring the habit of being a last gen adopter, something i learnt the hard way with the wii (out of thousands of titles only maybe 60 i like and those got launched between 2010-2013) so i am now aiming to buy a PS3 along the COBRA ODE thing for me to well pirate the PS3 games.But which model should i am for if i want to play PSone games on it?.

they are all PSX compatible.