I had decided a while back to get a navigation system for my HCHII. A couple of weeks ago, I was in Costco and saw a Cobra system with a 5" screen for $570 (most systems in this price range offer only a 3" screen).

I bought one and have been playing with it - it works great. I finally found a fantastic spot for it - it fits perfectly just behind the top of the gear shift console. I put a strip of velcro on the bottom of the unit and then another strip on the top edge of the little storage area just in front of the gear shift lever. It fits perfectly and looks like it was custom designed to be installed there.

(This model has a short rear window bracket, which I left on for additional support. I don't believe you can easily install similar models with those long, window brackets the same way. There is also a big difference from a 3" to 5" screen.)

I didn't think it would work well being so low and partially covered up (for good reception), but it works great there.

If you are considering an aftermarket navigation system, you might want to consider this one.