Hi! I have a power Mac G5 (1.8 GHZ 512 MB 160 GB) Serial Number XB40**QES. I want to buy an airport extreme card and found here on apple.com that the airport card I need is the M8881LL/A. But everyones at every store I´ve been keep telling me that a I need a special card for it, because the regular card just won´t fit the slot. Is this true? Thank you in advance for any help you can provide.