What do you guys think about Blaufergnugen's Sport Free Flow Air Filters for all audi models:4000, 80/90, 5000, 100 &200. It supposed to replace the bottom half of the air filter, for $149 bucks. I would like to try it, but would like your opinions first. Here is the link for all who want to see a picture of it and haven't: http://www.audiquattroparts.com/newly_available_2.htm