I think I see it now.
So first you would solder pin #17 of the LA6508 chip (did some research) to any of the 5-volt sources you pointed out, then you would install the EZI chip (or any other) as per their instructions. And if everything goes well, you should be able to play your legal backups without worrying that your v9/v10 laser will ever burn out, provided you use proper media (I have a 25-pack of Taiyo Yudens) and the slowest burning speed.
Did you have to do the same thing, JCWohlschlag? And would you recommend this romeo mod regardless if your PS2 is modded or not?
I was debating on whether or not to go Swap Magic or EZI chip 'cuz I was worried about my brand new PS2 dying on me before I had a chance to spend some time with it (seeing as I had a hard time finding one).
I'm sorry I had to hijack Accord's thread to find all this out and I hope he got his problem fixed.