I highly recommend a BT solution. Whichever one you get, they are very flexible, in that you can place the receiver at the best spot for pickup, and the PPC at the best spot for viewing. I wouldn't focus on the lack of cables, because many find that for long trips, you are going to have a cable to power the GPS and the PPC anyway. In that respect, if you are purely looking for a car solution a cabled one is significantly cheaper, and often more convinient than the BT one. There are cradles around that connect to power, and a GPS that you just need to slide the PPC in, start the map app and are ready to go.
With BT you typically need to connect the BT with BT manager, and then fire up the map app, and then start BT reception by the app. A few more steps. Some folks report BT drop outs too, but I haven't had an issue. Certainly there is no issue with a cable.
For a mounting system, you should take a look at ProClip system
http://www.proclipusa.com/ . If you are going to be supporting one car, these are outstanding mounts. I combined products and actually got the ProClip stuff that attaches to my Jeep dash, and then mounted an Arkon powered mount on it to hold the PPC. I wanted a universal holder as I have multiple PPCs. If I only had one, you can bet I'd have one of the ones you just slide the PPC in like a cradle.