Am I allowed to take sensor wires and connect them to bolts and an autonomous chooser?
Can you explain in a little more detail about what you want to do? You cannot make modifications to the 3-wire extensions, but there are several ways you can create an autonomous chooser using unmodified standard VEX parts.
I cut and rewired them
From my knowledge that is not allowed because you are modifying the wiring. We have created practically the same effect though by plugging jumpers into extension cords which I know is competition legal.
You can make a similar chooser by putting a skrew in a potentiometer, then turning it to select an autonomous. However the programing would be a little more complex than your selecter, it would have the same effect.
Nice idea, completely illegal for the VEX robotics competition.
From the Toss up manual.