As Selwonk says, the centre cubby and a re-radiating antenna is a really neat fit.
I have a TomTom Go300, looks great, no visible wires, just the small matchbox sized receiver stuck to the windscreen around the rear view mirror. If you want some pics I'll take some and post them. Looks as good as a factory install IMHO. It also means I can run the Talex in the cubby too!