I have just purchased a new Globasat BT 338 bluetooth GPS to replace an earlier model for use with my PDA in the car. The new one is SiRF III chipset and works well, picking up 10 satellites in the house and at least 6/7 satellites in any location I've put it in the car.
So far I've tried the glovebox, the space above the cup holders in the centre tunnel near the handbrake, in the door pockets, in the boot and in the small recess by the light switch. Most of which have metal between the sky and the GPS ie the car roof and it works just fine.
My next problem is to decide a permanant location. I had my previous one mounted on the side panels of the pacel shelf and connected to the 12v socket in the boot, but the new one switches it's self off if there is no bluetooth contact for 10 minutes so somewhere in side the car would be more convenient. My current thought is to double-sided tape it to the underside of the armrest. I very rarely have the armret down so it would be easy to get to the on/off switch and when I leave the car I could put the armresr down thus putting the GPS out of sight. It should be straignt forward to take a 12v and earth connection from the back of the 12v socket in the tunnel and feed the wire into the armrest.