MOD chips

[MAD!man]

Hey all...i got a few Q's to ask...

1) I have a stealth Mod Chip and don't know what type it is (isn't there like, a Stealth III and IV?) is ther a way i find out?

2.) Would you guys recommend i use an internal MOD chip or use one that plugs into my PSX's Serial Port (or whatever the hell that thing is...i forget)

3.) Is it really hard to install a mod chip...cuz i don't wanna ruin my PSX or anything...and does anybody have suggestions on how to not mess up on installing it???

Any help is much appreciated!