Sorry for the long delay between posts on this- work has been very busy. Just wanted to do a update on issues found to date & status:
- Mechanical: Very close. I’m about 90% done fabricating a bracket to move the airbag control module back about 1 inch. There’s plenty of room to move it back, and that should provide enough clearance for the CC head to be installed flush.
- Electrical: Very frustrating. The “plug & play” harness wasn’t even close. I’m probably lucky it didn’t blow up the Nav+ unit. Some of the problems were wiring errors (the GALA signal was on the wrong pin), some were omissions (phone mute wasn’t even wired), and one was just plain stupid (reverse signal tied high- Nav+ thought I was doing 80MPH down I-95 in reverse!). I think I’ve fixed everything at this point, but I’m going to go over it wire by wire a few more times. It definitely should be straightforward to create a real P&P harness for the 95.5 and up cars- you’d need to connect to the K-line (relay box under hood) and reverse sense (haven’t found it yet) but all other signals appear to be in the 95.5 stock harness. I’ll have to study the earlier car (92-95) wiring a bit more, but it should be possible to create a P&P adapter for those cars also.
- Navigation: I’ve been driving around with it in the car for a few weeks now, and even though it’s not 100% it’s still very useful and quite entertaining to play with, although you have to be careful to pick your spots to glance down at the screen- it’s pretty low in the dash. The display shows a lot of stuff (rivers, lakes, town names, route numbers) that I never knew about on roads I drive all the time- my 7 year old is also highly entertained by the compass and map displays. For testing I’ve been using a simple GPS antenna that came with the harness, and it always seems to get 6-8 satellites (8 is the max) just sitting on the dash. I’m almost certainly installing a factory triplex shark fin (GPS, GSM, Satellite radio) along with the upcoming repaint, but if I weren’t wiring in other accessories that need the GSM and satellite, I wouldn’t bother with the sharkfin.
- Radio: The radio portion of the Nav+ is most likely just a Symphony I with a very different display- the D-navi is a double-din unit made up of 2 single DIN chassis bolted together with a common faceplate- the top one has the CD slot and all the Nav-specific connections. The display and controls took some getting used to, but are straightforward to use after some practice. I am fighting relatively poor reception for the radio, but the prior owner of my 95.5 hacked the bejeezus out of the antenna wiring to add an aftermarket CD changer, so that problem is most likely specific to my car. Only significant usability issue is a finding quick way to mute the radio- the problem is you can’t just turn off the radio without turning off the whole unit, and then having to wait a bit for the Nav+ reboot. You can just turn the volume all the way down, or there’s a way to mute the radio through the menus, but I’d prefer something simpler. I may add a switch that mimics the phone mute (nav commands still get announced) if I can’t find an easier way to do it through the controls.
- Accessories: You can use any Concert or Symphony-compatible accessories, including Phatbox, iPod adapters, etc.. I’m not going there, but it’s been done, and the CD changer wiring is a completely separate harness/plug, so it’s very straightforward elecrically.
- Overall: It’s not the best functioning nav unit on the planet, but I knew that going in, and so far at least it looks really cool, has been very useful, looks really cool, has been mistaken for a factory install, looks really cool, is easy to use, and, most importantly, looks really, really cool 
