Of the ones mentioned this is what I want:

Apperance

pistol shifters - I want my with Pachymr grip that feels like a SIG
Different grills - depends on the design
Different lights- rear lights with LED's
A little chrome underneath the hood would be cool.
Replace all black hoses with stainless steel braided hoses.

Spoilers - a another retro one might be a possibility

Performance

Functional butterfly hood - these are supposed to be functional already to the throttle body unlike the charger and I am very much assuming that.

Quad exhaust - just take a piece of divider metal and it will look like the original then slip it off when you want.
superchargers or turbo charger - certainly a possibility
New ECU's - sue why not
Performance headers
Suspension upgrades - Air Ride Technology here we come
Brakes - make them 6 piston with low dust pads and larger rotors