Swap Magic is a pain in the ass. You would need to swap DVD's each time you want to play it. Not to mention it doesn't bypass region coding on DVD's so if your PS2 is pal & DVD is NTSC/US or NTSC/J then they won't probably work. Better to get a hardware mod done.
Well almost. Depends on the shop you take it to & also the person from whom you're getting it done. Just take down all the vital details of your PS2 before putting it in. Apart from that the modding process is safe. The chip just needs to be soldered in on the PCB.