saw with a special flexible blade. From inside the car they will puncture through the black resin stuff and start it up and cut all the way around the lining of the window, that's what is holding it in place, and it needs to be cut. The plastic clips and stuff are just holding molding in place, not the glass.
I bought mine from Z1 for like $70 shipped with the lower molding piece, if that would help you any...