Have you thought about running a tube in from the grille, under the battery, and to the bottom of the air filter assembly? Nothin' works like forced cold air induction. Also, if you don't mind my asking, can you explain the parts involved in that retrofit? I'm looking for a way to do away with the stock airbox, and I like what you've done. Thanks! -alan 83 320i 79 320i 74 02