I have the same experience. My original 30GB factory drive is a Fujitsu and is substantially louder than the 40GB Hitachi/IBM Travelstar that I put in.

So much so that if it's fscking I can't tell if it's actually working or has hung for whatever reason when it's checking the Hitachi/IBM.
_________________________
Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)