Installed 10.4.3. Took me six hours. Make sure your HD is in good shape: I had some issues, and the install bailed after 70%.
Just that I already had messed with the ATI drivers, but not with the WindowServer. So that one then crashed on start. Nice blue screen without a cursor. Actually not so nice. Target mode rocks! I copied all ATI* files in /Library/Extensions (or something like that 😉 to the machine, and et voila it booted again. Since I did fsck the drive like 13 times during those six desperate hours (and removed countless preferences and caches of course) the following install was fine. So if you like to avoid this then fsck before the 10.4.3 install. Probably before any bigger install.