I do still have all the brake parts from the parts car as well as the entire wire harness and computers. The intent is to use everything stock. The only things we decided not to swap over were the entire rear end....too much modification to make it work well, and the anti-lock component.
My transmission is a w5a580. Not sure how much, if any, difference there is. I know the Nag1 is from trucks mostly but they are similar. Not being a transmission guy I really cannot say.