So, to get the old "insert" out, the best way I found for me was using a punch and a hammer. I started with a small punch to get it going and then busted out the bigger punch.
I actually could not pry the metal open with a 24 inch pry bar.
To finish removing the old insert, I cut off about 1/8 inch of metal with a dremel around where I had bent the crap out of the strut casing. I'm thinking now that this was a mistake but I had no other way of removing the old insert. The new insert is in but the collar does not grab as much as it probably should.
I am going to reassemble the strut with spring and all tomorrow and go from there. If it looks/feels good, I'll put it back on the car.