Xbox 360 Rapid Fire mod Part 1
Shopping list:
-Soldering iron
-Solder
-Wire (I used 24 gauge)
-Something sharp to cut wire
-Torx 9 / T9 screwdriver, security hole is recommended.
Images:
This is the socket the every controller must solder to:

If you have a D1 Controller, this is the other socket:

If you have the D21 instead of D1, then you must solder you wire in this socket: