I was checking out a '98 323is and slammed on the brakes for an ABS test. In addition to the normal ocillation, there was a pronounced humming sound from the driver front wheel area. Is that normal? My '94 318i doesn't do it. ALSO, what do you think about $24,500 for the price? (Owner came down from $24,900). It has leather, computer, 5 spd, BMW CD changer, and 2 scratches (ouch).