How are these actually done? Do you still have a normal RA roof flap underneath it? Or is it a totally different method?

 

as far as I know the RA flap is completely different and doesn't go under the WRC style scoop

with the proper WRC roof scoops they are not very good for road going cars that are driven in the rain as they tend to not seal great under the scoop as you have to cut a section out of the roof for a new vent part and that doesn't seem to seal very well ,,, for this reason the internal bit on the proper one has a drain hole that you can add tube and run to the outside of the car for the water that gets in lol

iv got a blob RA flap fitted in my hatch and was a great mod

 

Ah didn't know that. It's primarily a track car to be fair, but something worth considering.

 

I also have twin group A vents in my classic and they are also the same and leak in heavy rain