I recently got a new stereo for my Cayenne, but to be honest, I am not that impressed with the aftermarket volume controls (looked at quite a few). So instead of spending a lot of money on a MOST-HUR and loosing my nice volume knob, I decided to hold off and just upgrade my bluetooth FM transmitter.
Unit
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After buying 3 or 4 FM transmitters, I settled on the following one. The reason was that is was clean, good power output, and I could adjust the frequency easily. There are few others that are pretty good, but this one met all of my criteria.
https://www.amazon.com/gp/product/B01GPXBD4W/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1
Mounting
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I mounted it like this because it is subtle and I didn't want to risk permanently damaging the leather. It works out great because the mic faces you and with your hand on your knee you can skip songs without looking at the unit (all by feel). The wiring is also invisible. Having it slightly angled down makes the skipping ergonomic and the red LED display isn't in your eyes. I didn't use the magnet mount since I wanted to reduce bulk. I just put some 3M regular mounting tape on the back of the unit and stuck it on. Seems to work fine. If it doesn't last, then I will upgrade to the heavy duty mounting tape. But no reason to do that unless I have to.
Wiring
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There are tons of options here, but this is what I did. First, I wanted it to turn and off with the ignition so that it auto connects and disconnects. This can also be done manually, but can be a hassle. I used this thread. Pretty easy and worked great:
http://www.planet-9.com/987-cayman-...ster-electronics/106153-bluetooth-phone-auto-connect-key-insertion-finally.html
Now take off the passenger side top panel with the cigarette lighter with the torx screw. I have the Bose so may be different otherwise, but you pull the little plastic "Y" looking piece out first to access the screw. You can now pass the end of the FM transmitter to the passenger side with just your hands...its pretty easy to grab it by feel.
At this point, you could just plug it into passenger side and it will be clean look. But I wanted more options. Therefore, I got the following unit. This has an extra USB port and extra outlets. It also has a digital voltmeter, which can be handy.
https://www.amazon.com/gp/product/B01LNEMJRI/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
I wanted to make it clean so removed the cigarette lighter socked from the housing and plugged the blue unit into it. Then I tucked it all in behind the housing so you can't see it at all. Here is what I am talking about:
Next, I had to find a way to mount the blue unit. The goal was to make it unnoticeable, but still accessible. I tried using velcro, but it wouldn't stick to the material at the top of the footwell...it is sort of a felt like material. I tried another option which turned out to be better anyway. I placed two strong earth magnets (1" diameter) above the little liner and another below it. For the one below it, I used an epoxy coated magnet so it wouldn't break. The nice thing is you can position the mount anywhere at that point. Then, I mounted a SMALLER and thinner magnet on the blue unit. This will allow it to break away from the "permanent" magnets. I used the 3M HEAVY DUTY mounting tape, not the light duty stuff. You can then tuck this all the way back so noone will ever see it nor the wiring. If you need, you can just easily pull it off the liner and it snaps back easily as well. Here is the final setup.
Overall, it works well and the FM transmitter is powerful enough to provide decent audio. The mic is decent as well, but not as good as a real install so don't expect miracles. You can't see any wires and it looks pretty clean. One of the nicer features is the ability to skip songs very easily since the button is right by your hand (can't do this with an aftermarket radio). I would still prefer a MOST-HUR + aftermarket, but $40 compared to $1200 is a big difference (though I wasted a lot trying different components). But it was a fun little project.
