Oh really? I thought I had to wire up the tacho to the ecu or something?What do you mean, how much wire? They're plug and play.
mine is a pre-facelift R reg (1998)It all depends really. On the older cars you will have to run a tacho wire in I believe. Try it first anyway. You never know. Mines a coilpack and already has all the wiring. What year is yours, as that determines the instrument cluster that you will require.
Ok so you've got the older mechanical speedo clock set. Yes you will need to run that extra wire in. Unfortunately you'll have to wait for one of the other members to tell you where to tap into on the dizzy as I don't have one. Hope you get sorted.
here,s 1, but a lot of broken links tho https://www.micra.org.uk/threads/k11-pre-facelift-rev-counter-wiring-procedures.40661/