So explain my car.........with the inner arches cleaned to every few months?
I was only referring to the use of plastic wheel arch shields/liners (as fitted to modern cars) not the routine cleaning of inner arches. By comparison I have plastic arch liners, never clean under the wings and the flitch panels on my car are virtually spotless around the air vent ducts. I'm not saying that the vent ducts are not rust traps in themselves, I'm merely saying that they need not be, if you fit plastic arch liners and protect them adequately.
Did you actually have such plastic wheel arch liners fitted in your case, or did you just clean under the wings regularly? If so, how well protected were your panels and how were you cleaning under there? Some methods of regular cleaning can strip away protection, exposing the panels to further corrosion and making matters worse (jetwashing particularly). Similarly the commonly used bitumen based under seal can trap moisture behind and cause this sort of rot, particularly if the existing corrosion has been simply painted over with the stuff, which is a classic previous owner "bodge" that is all too common.
We evidently don't agree on the importance of classic mini air vents though and are clearly unlikely to, so there's little point in debating the matter any further.The important point is that the OP now has both perspectives on them and is free to reach their own conclusions. If the OP still want's to block off their vents and fit speakers in the holes, then I'm sure that they will still do so, it is a common mod after all. But at least they will now have the necessary information to make an informed decision about doing so.
from an audio reproduction point of view, this is a terrible way to install speakers.
Quite possibly, but then I'm an old git and my appreciation of acoustics is almost as questionable as my concept of what is "cool". As far as I'm concerned if the speakers point into the car then "they'll do"!!
...... Someone such as yourself would probably consider that to be blasphemy though!
