There are no cables with the Tom Tom unit except the power cable.
I have drilled a hole under the rubber mat and fed the cable behind to pick up a switched live.

The unit is then on mains power as soon as i switch on the car, but does not drain the battery when switched off.

The Tom Tom does have an external GPS antenna if you want to fit the unit somewhere that does not have a clean signal, but fortunately the lid does not affect the signal at all. No other wires are needed which has made this a very easy addition to make.

The unit has a built in speaker so i have not had to worry about connecting to the factory stereo either.