Yep I've done this on my mk2,have led brake,side lights and indicators in the rear clusters,you may need to make the holes in the rear clusters abit bigger with a file as they are to small to fit the heads of the bulbs thru and also you will need to put resistors on the idicators as the led bulbs make them flash too fast becos they draw hardly any current it makes the circuit think there's a bulb out.
all lights are now much much brighter so I'd say it's worth doin
