it's an arse ache, the nd0 6 spd gearbox isnt a straight fit into the mk2 clio, will need custom driveshafts/mounts etc and the JC5 1*2 gearbox is not a straight fit as the bellhousing is different on the megane engine, drilling and tapping the block will be a ball ache too!
Don't believe the posts of 182magoo either, he says he has done the conversion as he sold me the engine, his stories changed swiftly though when I actually got the engine and realised several things he said he had done weren't possible!