i did this change a couple of weeks ago if i remember correctly the size was 6.5 inch but will check and let u know problem i found that the speaker was slightly smaller by millimeters and i had to drill holes into the door but it was only into the metal and didnt take 2 seconds, Wiring was easy just had to snip the origanal Micra connector and there are + & - wires going into the connector from the radio which u just connect up to the speakers, you wont have to remove the grill or anything you wont be able to notice you changed them in terms of looks,also if it helps and you have the original micra stereo from pre facelift the radio will take rear speakers as the output wires are there on the harness i cut into my back side panels and mounted some they look quite good
