Help regarding modding a PS2

I know its rather lame for this age, but since I never owned one, I have few questions:

Are there different ways (available in India) to mod a PS2 slim Which is the best method and what is its rough cost and availability in say Palika Bazaar

Is it possible to attach USB Hard Drive to a PS2 slim and play isos through it. If yes, which kind of modding is required for the same

Thanks in advance