I agree, have the pro's do it. My brother tried to do his and he cracked the new glass because he did not properly remove the old window leaving a good base for the replacement.
If you do not remove the original window and leave enough of the original sealer in place you may not get it to seal, or worse yet it will crack from some part of the pinch weld putting pressure on the glass. I know several body men and they don't even do them, they say its best to let the auto glass specialists do it, they have the tools and all the right chemicals, which btw can be extremely flamable.
[This message has been edited by elcamino (edited 05-30-2001).]