Shift kits.. do you really need one????

If you are not going to hot rod the car, not needed. My 66 Dodge went 120,000 miles with no shift kit and had to rebuild because an O reng was pinched by the factory when assembled. If your a goimg to race 9i.e. street/strip thne put one in it. Trans Go kits are very good and don't require all the work you are proposing. If it's a 904 than I would put in a shift kit to keep from losing the second gear band which is the weak point of that trans. My opinion at 71.