when you go into the red, you turn round waves into square, and that means you are changing the timbre sounds on the record, not just the volume. if you think you have a better ear than the producer, then go ahead and overdrive the mixer.

if you have a knowledgeable sound guy, he'll be making sure your levels are maxed at the pa. if you are coming out of the dj mixer too hot he can't do anything but turn you down in volume!

this is one of the reasons i don't like those pioneer mixers. they encourage the "4 bars into the red is ok" attitude. new djs - leave the amplifciation to the amplifiers, and keep your mixers in the green!