If you're accustomed to the speed of wireless, then the speed difference between a 16 bit and 32 bit PCMCIA is not going to matter much. Even the slowest byte mode of 16 bit PCMCIA is a little less than 4 MB/sec and I'm certain the 2400 supports word mode at faster rates (which would be 20 MB/sec; the card might not, but all cards I've ever seen support word mode at least, which is a about 7.8 MB/sec).

Try it. It may have been either the older PowerBook which was a factor, the driver, or both.