On Saturday I am going to get my cartilage pierced, and I've have been reading all this stuff about how its bad to get in pierced with a gun. Should I get it pierced with a gun or needle? And I was wondering how bad it hurts.

Always get piercings done with a needle. Using guns is unsanitary as they can only clean it with an alcohol rub so it doesn't kill blood-born pathogens like HIV and hepatitis. Also, guns can shatter/damage cartilage. With a needle, its hollow so it won't create any damaged tissue/cartilage. Of course it is going to hurt, you're having a needle pushed through your ear but it isn't unbearable otherwise it wouldn't be such a common piercing. Eat a good meal beforehand, have someone there to hold your hand and just relax, it will be fine. Make sure you follow after care instructions carefully and try not to touch your new piercing, if you have to make sure you have clean hands! Good luck.