Help me figure out what these mods supported.

My guess is that the previous owner was buying better (bigger) parts for mods that he planned on doing in the future and then either lost interest or money.

The 24lb injectors aren't big enough for a good blower and my guess is he planned on running bigger heads on the car when money permitted him to do so.

An adjustable pressure regulator is standard stuff to buy, especially when putting a little bit larger injectors in.

The "manual fuel cutoff switch" is so someone can't steal the car without knowing where the switch is located.

Plus there is no indication that the car received a larger fuel pump to accomodate the higher fuel demands of a charger.
I don't think this car ever had a blower and if it runs and drives real nice, what difference does it make.

Good Luck

With 4.10's in the back my crystal ball says it definitely didn't support a blower.......