On a 1999 model car, you should have the plug behind passenger kick panel that makes it a easy fit. Also TC switch should already be up above radio, with a small tray to left of radio.
Its a seperate screen on the Carin, unlike the Siemens system I have in th MV6 which uses the MID (or rather a replacement display called a CID). The Siemens system is undoubtedly the better system, but holds a hell of a price premium.
Both systems are capable, though the Carin is quite sluggish to enter a destination with the newer maps. Neither system, surprisingly, can do postcodes.
Anyone going to any meets that I attend is welcome to see both systems in action.
It is likely I will shortly be removing the Carin from the MV6, so that will be for sale in the not too distant future, suspect around £75 + postage. I have a spare Siemens setup for prefacelift (NCDR1100, Colour Display, 4 disc CD Changer) sat gathering dust, probably looking around £300, but it will require minor rewiring (preferrably on Trafficmaster loom) - I have a conversion lead for CCR600/800