So I have cut the top off and it's resting in place. I will cover how it stays in place and the trim that it take to get the scal finish so that it looks like the real D-90.
The razor saw is a must to get the clean strait cuts with no loss of marerial of the body.
The Channel is what is needed to give it the look like it was ment to be this way. I have more to do of course but it's a start. The cutting the roof off and adding these parts took only a 1/2 hour to do, this is the easy part.