Plug and play and quick to do. If your bendy enough you can move the passenger seat back, lie in the footwell and get the unit out (it is much easier with the glove box out). Think one unit I replaced was £45 plus vat,
resistors had gone on that one. Incidentally there are more screws in the glovebox than you would think entirely necessary, you need to poke around the edge quite carefully to find them all.