I'm thinking of getting an Action Replay for my DS, just for the fun of being able to screw with games. have a few questions about it for anyone who's used/owned one.

1. Do the cheats affect your games in negative ways (i.e. in ways you don't expect or intend)?

2. Are cheats permanent, or can they be undone?

3. Have DS's been damaged or messed up by it?