Hi Allan, We replaced the standard unit with a Clarion VX-580 unit, we went through Monster audio so got a perfect fit and finish..our unit is Sat Nav ready as right now we dont require the navigation side of it, but plug in the micro card and off you go..there are a few threads on here already where members did a bulk purchase of head units so a search on here will show some ideas of what others have used.
Good Hunting Mate
KAA