Just a recommendation, don't change too much at once. Start with known things and change one at at time. Unless everything goes perfect, and they rarely do, you will run into difficulties because 1 thing may not work right and you may think it is one of the new things you installed but it may turn out to be something else.
Just a tip on the shift kit, make sure you get the latest manual, we update it all the time to improve it, actually just made a few updates 2 days ago. If you have any questions just shoot me an email. email@example.com