In fact, I myself am puzzled by that official info from MS.

1) Windows does not rely on bios to manage hard disks. On my 5 year old Mobo I installed a 180 Gb hdd without any upgrade or problem. On other machines bios does NOT detect hard disks which then windows 2K/XP actually sees and manages regularly.

2) On Windows 2000, I needed the registry change to let windows 2000 Server see the entire disk size, but that was before W2K SP3, and did not require anything more than that specific registry entry. Also, without that entry you would simply see a smaller disk. No crash involved, no other issues.
You would expect that Windows XP behaves similarly. I have not installed a fresh copy of Windows XP w/o SP1 on any machine with >137Gb, but the worst case scenatio is that you only see 137Gb at the beginning.

Maybe a research on MS website will provide more details about this...