I'm with geeteeohguy......keep the Silverglaze. Georgeous color in the sun. Look at all interior color options. Pick the one you like best, besides Black of course. Almost anything but Green will go well with the Silver.
I recommend against 4 wheel disc brakes. Most of the stopping power is transferred to the fronts and you need a proportioning valve to limit the pressure to the rears to prevent lock up. You really don't get much benefit from the rear discs and if the pressure is set too high it will go in to a spin under heavy brake condition. Eliminating the rear disc conversion will free up a considerable sum to invest elsewhere with more benefit.
Like Bluesbrother said, an electronic conversion that fits in a stock distributor is great. I have a Pertronix III in my 67 Camaro and you have to look close to see there are 2 wires instead of 1 coming out. I also did the Black Flame Thrower 3 coil that looks stock but puts out a much higher voltage. You can open the plug gap to .045 and get better throttle response and performance.
Adding the Ram Air pan to go with the manifolds is a personal choice. I don't really like all that metal hiding the engine and as amechanic I know the actual gains are very small over a free breathing air cleaner. For a race car that needs every bit of cold air it can get for optimal performance, they were good. The original louvered covers are rather restrictive at top end performance.
The AM/FM and 8 track are just period correct goodies that may make it more desireable to a potential buyer, but remember, they can get the PHS too and see that those aren't original to the car when it comes time to sell it. Dressing up a Pontiac for a higher resale isn't like a Chevrolet. Pontiac kept the build records and they can be referenced to authenticate a car.
Now, pics are in order here....