get the biggest grinder you can. not a 4". i would cut through the a and c pillar. and through the sill and through the rear beaver. basically leave as much as you can for your panel beater to work with. find the factory joins and cut on the other side of them. then your panel beater can un pick the factory spot welds and replace it as one section as factory.
the cut through the floor is going to be a pain. a real pain.
wear a face mask/googles and ear protecting. be careful.
