The older models are fairly simple to modify yourself, just don't go at it like a barbarian.
The new slimline ones on the other hand are a pain in the ass, unless you're really good at the game "operation". If so you can buy ghost clips for a couple bucks that go over the sensor that relays the mssg to your ps2 that the cd top is open.
Whichever model you have, you'll need to use a swap magic version 3.6 disc (I believe) boot disc. This disc needs to be loaded up prior to every single time you play an imported game.
In the end I just coughed up 340 big ones for a universal ps2. Due not only in part that I freakishly fucked up 3 ps2's in a span of twenty-four hours, but for mainly that it becomes a pain in the ass to boot up the swap magic disc on an older ps2 with a shoddy lense.
Go here
http://www.clearxbox.com/site/pages/cat_xbox.html
Also, it is actually "Per se"