FileForums - PSX Emulator

Hey guys, what is the best PSX emulator. I have been reading on the internet and read something where you could hack games. I would like to try this on some of my PSX games. To make them more challenging and funner. Is this possible or do you have to have to be a computer whiz to add simple hacks. I fooled around on some older NES emulators and they had a create your own codes where I could give enemies more life and could have double weapons and stuff. I was just wondering if there was a PSX emulator out there with a similar function. For example in Castlevania Symphony of the Night I would like to give the enemies 4x defense and bosses 10x the life. But make all the enemies drop their items a LOT sooner. I once played in luck mode and still had to kill over 100 enemies to get a sword. Oh and have a code to remove that cheesy alucard shield. Or in Final Fantasy 7 make it easier to level up and make Sephiroth actually hard. I purposely put on my suckiest equipment to fight him, how pathetic is that when he is my favorite boss on any game ever. Anyway is this stuff even possible? Oh and if I bought a gameshark for my PS2 is it possible to make your own codes using any kind of application on my pc or anything.