Foolishly I went ahead and installed this on my G5.
The G5 has always been lousy with airport with signal strength so low it requires an external antenna (and even with the Dr. Bott the signal is low... a G4 in the same room is full power).
Anyway I was getting about 50% 60% signal strength before the "upgrade", now I have about 10%-20% signal strength (the G4 continues at 90%).
Oddly enough I now pick up 2 other networks that didn't appear before and I'm having a problem with drop-outs....
Sigh. I never learn. If it ain't broke....