I'm not a guitarist, but I think it really depends on what kind of distortion you're looking for. What kind are you looking for? Like, a real crunchy kind? Heavy? And by scream do you mean pinch harmonics, or feedback? If you want feedback, play a little, put your guitar close to the amp with the gain up, turn your guitar upsidedown and shake it...it has a really cool effect. Saw QOTSA do it.