a chip in the middle of the RC cicruits which after research appears to control the car.
Until you are familiar with the RX/TX2 I would suggest you don't connect the Arduino to them, I have no idea how much current would be drawn by the car and in the few cars I have opened most of the decoupling capacitors are labelled on the PCB but just not installed I suspect the same goes for flyback diodes. This is probably not a safe environment for to learn in.
Again thank you for the help I am starting to see where this is going.I have attached an image to make sure I understand the pins before soldering.It wouldn't be a good idea to solder on the top would it? just looks to be more space there than trying to solder exactly over the dot