I've got the Nokia CARK-91 installed. The good thing about the unit is it takes LOADS of Nokias. 51**, 61**, 62**, 63**, 71**. It also plugs into my Pioneer head unit (7400MP), for a far superior sound than the standard enclosed speaker.
The antenna looks like a tax disc and is attached to the bottom left of the windscreen, so no holes in the body, and no nickable bits!
The only downside is, where it's been wedged in, to the left of the silver centre console, the three temp controls are slightly misaligned, but friends have said it's just me being pedantic.