Will - Overkill is very knowledgeable of this and we have talked about this in the past. I would try emailing him and get his opinion. I know he mentioned it being louder and adding a little boost if I am not mistaken. I have never tried this, well I tried welding on a junk case once and it was very poor aluminum and welding didnt work out so well lol. I never tried one on a car with the holes blocked off.