I bought this after seeing your post... A+! Works perfectly and fantastic sound quality! :dance:

Got the Logitech this week and tested it out, and it sounds like crap. I lost a lot of bass and the hi's sounds like a metallic synthesizer. Going to return it back to Amazon and get the Sure-Electronic board. I got a chance to listen to Quanger's car with the Sure-Elec. board and it sounds 100x better than the Logitech. So anyone still in doubt about this mod, just go with the Sure-Elec. board.

Boost7,

Can you tell us how you have tested the Logitech Adapter (what did you connect it to)? Note that Logitech adapter measures flat down to 20Hz (less than 0.5dB roll off). You can have a rolled off bass if you have it connected to the source with very low input impedance. Anything that has input impedance at 10kOhm or higher should not affect the bass frequency response. The device has not been designed to drive headphones directly. In my system it souds pretty good and here is what the whole setup looks like.

http://s8.postimg.org/8dkx3t3ox/20141102_142612.jpg
http://s8.postimg.org/6n1w2bm5t/20141102_142427.jpg
http://s8.postimg.org/xv3bnelf5/20141102_142356.jpg
http://i60.tinypic.com/96hrmq.jpg

Before permanently installing the Logitech, I tested it in my garage with the wall outlet power, then paired it to my iphone, next, I used the headphone jack and plugged it directly plugged into my AUX input. I even tried the RCA to headphone jack with the same result. So not sure if I got a bad unit or not, but after listening to Quanger's car. I'll just go with the Sure Elec. board.

do you have LCI or pre-LCI? Perhaps there are different versions of CCC or Aux board (different filter). Another thing to check for is EQ settings. If you use EQ (intentionally or not) your phone may apply EQ to headphones output only and not to BT stream. Something worth looking into.
As I have mentioned it previously, I have Logitech adapter installed in 2 cars. One is '09 shown on the picture (manufactured in feb of 09) and another one is '10 (manufactured in may of 09) with USB input. I removed caps on the Aux board in '09 car and have not had a chance to remove them on my '10 yet.
PS: the previous version of Logitech Bluetooth adapter (it looks different, larger box) had the rolled off bass which I've confirmed with measurements.
Hope this helps.

tpaxadpom, thanks for the reply. I have an 05, so that's preLCI. No need to do any other test trial, I'll just go with the Sure Elect. board and not worry about having the correct version or doing this and that just to get it right. Plus the Sure Elect. takes a 12v so it's much easier to wire up, vs. the Logictech requires a 0.5v from a USB adapter, this will require me to get some additional parts, like a cigarette lighter to USB and the USB cable to barrel plug that fits properly. Too much to monkey with just to get BT audio streaming.

gotcha. Though I would highly recommend getting a plastic box for Sure Elect. module to avoid short circuiting. You may have one laying around with office supplies or something.

Glad to hear it , as I am in the process of installing the Sure myself.
However I do suspect that maybe the lousy results some of you get with either BT IS THE LACK OF ground isolation or more than one BT active and interference with one another.

Just my 2 cents worth.....

Like I said in the previous post, after comparing the two, the Sure board is much easier since it requires a 12v install. That just makes it much more easier for me or anyone else. The Logitech can be done, but will require a few more parts just to get the correct power, why add more component to the mix and overly complicate things.

+1