I'll start by saying, I have not replaced those bushings in my car. I have replaced the subframe mounts however. I would support the car via jack stands under the frame so the subframe is free to move....then remove the bushings and re-install. Best to not let the subframe hang that way longer than necessary.

How are your subframe mounts? They usually collapse and degrade.

Keep in mind, you will need an alignment after messing with these bushings as they affect caster. Also keep in mind, almost nobody in business knows how to align these front ends. Also, the fine adjust for caster in the king pins and those eccentrics are typically frozen even if properly greased.