Ouch. Lufc is correct. You say you already have the HD? Atleast that's kinda what I got out of your first post.
In answer to your question, you don't need anything other then HDLoader. That will do all the formatting and ripping. It's very very easy. With PS2, network adapter, hard drive, HDLoader and games.... your gravy.
So with the slimline PS2, I'd say maybe pick up the older larger version cheap off Ebay. Maybe a trade for your new one? I'm sure a friend would trade you straight up. Or lastly, have a mod chip soldered in so you can play backup versions of the games you currently have.
