Man, I can't remember how many times I was under that car and never came close to dropping the k-member. I'm sure it's never been out. A couple of options work well. Any support under the oil pan if the car won't have to be moved while the k-member is out. This could be a piece of plywood on a jackstand or a simple wood frame (4x4s with one directly under the pan). I have also pulled many k-members in wrecking yards with support this way. I have also used a piece of steel across the frame rails under the water pump snout, but I'd opt for support under the pan first.
