I spent an inordinate amount of time studying all the issues here with the D3 and the bypass, the BT issues with phones, the route inconsistencies with the Nav, etc...
I bought my unit on Ebay and the price was good enough that I could also buy a no questions warranty from Square Trade and I still came in much lower than Crutchfield with the new rebate from P. I did buy a Sirius tuner from Crutchfield so I didn't get off totally retail free. I bought it from them because they insisted it was new. I could only find refurbished on Ebay. The price wasn't that different anyway so my peace of mind won that battle.
I was planning to do the bypass myself but a local installer in Lakewood, CO was willing to do the installation and the bypass. He had the same information as everyone else does here. He guranteed the work and the bypass and the price was reasonable. I usually do all my own work like this but in this case it was worth it to me.
Everything works beautifully and the bypass was flawless. Nav, DVD's all work fine. I had the same issues with my TREO 750 that everyone else has with the bluetooth compatibility but the Jetware software fix works just as advertised. I find the D3's route selection to be the same as I would choose in the Denver area so no problems so far.
All in all it has been a good experience and the info I got in this forum helped a lot. I registered so I could post a good report for others who might be thinking this all sounds a bit intimidating.
I am very happy with the unit and all the features. Definite improvement for me. Having a DVD playing and going down the road was a little disconcerting but not having to stop to input addresses to the Nav is essential. I wouldn't install the unit without the bypass.