You what??
182 is a completely differnt car, it doesn't have a bonnet vent.
No, you don't need the rain catcher, there isn't anythign important under there that wull get very damaged if it rains.
if you stick a K&N on there, its lower then teh std air box, so the rain cather wiull fit.
For the record the vent on the valver bonnet is, becasue of the bulge a low pressure area, so air gets drawn OUT of the engine bay via it rather than in, hence sucking out the hot air from around the manifold ont eh valver/williams.
So fitting one above a K&N etc on a 1.2 will onyl draw the hot air from the engine bay towards the filter, actualy making the car SLOWER