70mm TB is way too big for that setup. 65mm is a better size, but you wont even pick up much from it with stock heads. If you are on a budget you can get a explorer 65mm throttle body for cheap and change the brackets over from a mustang and use it.

19# are still more than adqueate for your setup, but I would get an adjustable regulator so next time you do dyno you can tune it a little. I would wait till you get heads and do everything else you wanna do for the tuning.

The car will run fine without any tuning, the EE IV C is great computer for growing with. You can make a little more power with tuning, but the car will run fine.

If it were me, I would get all the parts you would need now, If you are plan on doing heads though get 24# injectors. Id wait till you had heads to do it all. Once you pull the intake you arent very from doing the heads, no point in doing the same job twice.