Wheewww!!!
After battling with this hackintosh 10.5.3 update for days, i almost win the war now...

I've been trying to update from my stable 10.5.1 (IATKOS 1.0 r2) using the downloaded official updates from Apple site.
So i jumped directly from 10.5.1 -> 10.5.3
After installing the 10.5.3 updates, i've the following problems:-
(1) System hang after install (at the grey Apple screen) - reboot a few times, then discovered the PS/2 keyboard/mouse not working, so changed all to USB keyboard and mouse - OK.
(2) No sound - this is same as 10.5.1, just install the ALC888 driver and patch it up with the HD patcher. (mine is ALC 885) - OK.
(3) No QE for GPU - just download latest Nvinstaller v.52 and run. - OK
(4) SATA drive not regconized - my DVD burner not detected no more. Previously, can detect the DVD burner and 1 SATA drive.
So i left 1 problem only...maybe fix later...really sian liao!!!!
Another weird behaviour, now cannot shutdown properly or restart. Everything seems to shutdown but it somehow can't connect to the mobo to inform to shutdown/restart. No big deal though. Just manual press reset button.
One big benefit can see...boot up time is super fast even on my slow 40GB IDE hdd... previously boot time is very slow!! It is now even faster than UBUNTU boot up time!

Is my problem the same like yours? Instead of using PS2 keyboard/mouse, should use USB keyboard/mouse instead? Would try soon and let y'all know.