I have an FM transmitter/charger coming from my ciggarette lighter. It's all wired from the back under the dash. There is a stereo connector coming right up through the first cupholder so I just plug my phone in and it sits in the cup holder. The charger is wired trough there as well. It works perfectly!
'99 Big Turbo B5 A4 (the red one) ^^^
'91 Ford F150 v8 5spd
'05 stg 2 scoobie wagon
'82 VW rabbit vert