yes it does save space...but it also costs a lump sum for em.....unless u get these cheap imports off ebay that are single and double din combination sat nav, dvd, mp3,wma and even some with built in tv tuners. otherwise if u get a more establised and reputable brand then u'd b lookin to pay no less than £900 through to £1500 for a unit.
Although they have on board GPS, the sat nav function usually functions via loading up the data via CD which u insert 1st to load up the maps then can b removed there after where portable navs are cheaper, portable, plug & play and easily updated:-)But stil, lets not let that put u off the idea, a lot of users have paid out for them as an investment and have been happy with them so its entirely up to u what you go for. Main benefit is the removal of havin a unit coming off your windscreen. and assure one that has a removeable facia plate for security as these cheap import units i'v seen on ebay dont have that function and are easily stolen. however they are wayy cheaper to buy than the more established brands but i wouldnt trust them personally as theyr more prone to failure sooner.
