Depends on the dealer. If it's a bad factory part, then they should replace it under warranty and not charge for diagnostic time. If it's a code caused by the aftermarket parts, (sensor out of range due to airflow or you not properly isolating the MAP sensor from boost) then they'll charge you 1/2 hour for reading the codes. Unless they are pricks and want to charge you a 1 hour minimum. Shouldn't be the case just to read codes. There is a possible problem with our MAF's. One of the guys in our shop was a Mazda master tech and just came over to work on BMW's. He said that the coil packs on the 1.8L (99-00) and the MAF on the 99-02 pro's were problem children. No recall, only replaced on a customer complaint basis under warranty.
