Dension is a very expensive FM transmitter.. Same money you want to look for a Parrot Mki9200 Best solution for ipod + bluetooth handsfree.
Features..
Charges the ipod and is a direct link on the line-out (strip at the bottom, not the headphone jack) for optimum sound quality
Shows all playlists, artists and album art etc on a little removable screen approx 2.4 inch..
Comes with a steering wheel control that works exactly the same as the ipod, (can be mounted anywhere you like, simular to the screen)
Also has bluetooth handsfree connectivity for your phone, screen shows all contacts and and images with contacts.. No need to use ipod or phone, fully handsfree, double mic for better sound quality for whoever your talking to...best solution imo for ipod in the car as its also very good sound quality for handsfree too.
www.parrot.com
Will all link into your car without changing anything from standard, very subtle and stylish mod.. Most cars with bose will need an additional SOT lead to adapt wiring, and if you have a fully amplified system some of the mainstream supplier such as Autoleads dont make a SOT lead for your car, however there are ways around it.
If you want any more info, look it up, or give me a shout.