I usually use a Gameshark or Action Replay for one reason: To get things that can be done legally within a short amount of time. Such examples are max DVs. It can be done legally, but the odds are so slim that your game clock will have reached 999:99 by the time you do get one, and you'll have to restart anyway. It was SO much easier to get max DVs in GSC.

Of course if you want me to give out some codes, just drop me a PM.