i have the same mainboard (p5kpl se), cpu dual core 5300 (not core duo), nvidia 7500 le, 1 gb ram s3+, hd sata maxtor, dvd-rw nec pata.
i installed iatkos 5i and add support for vga with natit and with r1000 for lan (realtek gigabit)
the system is fully working, but when i shutdown, osx stop but the main board do not power off. Simply push the power button.
The system seams to be very stable and fast