ive got a pop up sunroof in my mk2... the owner before me put it in...
it doesnt leak at all... wen its popped up its not that loud either... it does get pretty hot inside the car wen its all locked up though... but driving for a min with the windows down soon fixes that... or even if its a nice day i normally jus leave it poped up a bit n jus lock the doors...
if i was to own a mk2 with no sunroof im not sure that i would put 1 in... prob not jus cus id rather spend money on other things... but its pretty cool i like it haha