Damn good idea. few tips for you, depending what shape micra you use.
The ca18et goes straight onto the n13 sunny zx gearbox using the bluebird release bearing carrier and then use sunny drivshafts aswell. The gearbox on the later sunny zx's were Lsd as standard .
Was planning this sortof conversion for one of my n14 sunny's when the silvy gives up the game, allready have a rad and a pair of drive shafts just need the box and some other bits and bobs.
You might want to put the brakes on it , but saying that micra pads come in racing material aswell funny that considering they are as fast as a trolley as standard.lol