I've put mine by the cup holder and it works well and was really easy...
This is what I did: i removed the trim just above the cup holder and fed the wire from the back of the stereo
and just above the cup holder I then refitted the trim and the wire is jammed just nice between the bottom
left where the trim meets the cup holder and the phone just sits nice in the cup holder
thats prob where im gonna put it but im after something to hold it securely in place, ive got a trackday app that will measure various performance factors for me to look at after each session, for this to be accurate it needs to mounted firmly