I have done it (there is a thread on it somewhere) and its not as straightforward as crankshaft suggests. The rally frame is different so the rallye airbox will not fit on an enduro You have to mod the enduro air box to fit the carb inlet and build a inlet tube. If you use the stock rotor, then you can use an ignitech ignition system, if you use the rallye you need the rotor to go with it. You can get tank plates from ktm to convert the stock tank.
My bike got nicked, but if i did it again I would build a new air box from carbon fibre rather than bodging the old one.