Ok so I have now installed the Kenwood DNX 9140 into my 04' Targa. A few points for those who might want to use the existing Bose speakers which I did. I have the M680 pkg (cdr 23 & 6 channel MOST amp) which gives me dash, doors, & rears as well as a sub by the passenger footwell. I am using an Alpine PDX 5 amp. The fronts- tweeter/midrange are 2 + ohms & the doors -midrange are also 2 + ohms. The rears are 4+ ohms tweeter/midrange & the sub is one ohm & is not separately powered. This drove me crazy since the documentation is all over the ballpark & of course this is a 996 & not a Boxster which I assumed would have much of the same wiring but--. Bottom line I connected the doors & dash in series which gave me 4 + ohms as measured at the harness. To do that I found that "Pep Boys Auto Stores" (national auto parts store) carries male connectors for the Bose premium sound system installed in many GM cars. I then connected these to the Alpine speaker wires & used heated shrink wrap insulation which was perfect to allow the connectors to be pluged into the existing female factory MOST harness without a matching male plug. I needed only two jumpers to connect the negative to positive wires of the Left & right dash/door speakers to enable the serial connection . Then I connected the other two wires positive & negative back to the amp for each side. That required only two channels & the rears took the other two channels of the Alpine. After a great deal of angst & a recommendation from Greg who has posted here & is an engineer as well as a former installer, I simply turned the gain way down on the Alpine for the unpowered sub channel & the system sounds just terrific. I can use all of the head unit controls & I have true 5.1. I also used an audiovox rear view camera which worked out beautifully. Finally there have been many posts on the AVIC3 & the bypass hack as well as the speed sensing wire. The Kenwood has no wire for speed & the bypass is super easy. It just require that the ground wire be connected to the parking sensor wire. I do not recommend placing the GPS antenna under the alarm sensor at the front of the windshield. IT is just way to much effort & you are likly to break something as I did. In retrospect I would place it under the plastic cover in front of the windshield by the trunk on the left side of the battery. It only needs not to be blocked by any metal going to the sky. I did this with the Sirius antenna & it works great. That will save hours of hassel. If you have a 6 channel system it would be even easier to get a new 6 +1 amp which eliminates wiring speakers in series assuming the amp is stable down to two ohms like the Alpine PDX 5. I also considered other alternatives such as wiring the doors & sub together which I may still do since the plug in harness has worked out so well. There are no wire splices with this setup. But at his point I am really happy with the sound. I also placed the voice command button in the ashtray which keeps it out of the way unless used & is also a very handy place for it. The microphone will eventually go where the factory mic is located behind the plug next to the instuments but for now it is zipp tied to the steering adjustment handle below the steering wheel. People tell me the bluetooth sounds like a high quality speaker phone on their end with no odd noises.
Question: Is there a separate wire in the factory cdr 23 plugs for the antenna control wire from the head unit to be attached? Since there is no powered antenna I am wondering if the antenna might in fact be amplified thus requiring a connection to the head unit in addition to the plug in antenna? If someone could point me to a wiring diagram for the antenna and/or the cdr23 plug i'd appreciate it. Thanks Cris