Here it is. Finally finished.

@gaz919 Thanks for the wishes and warnings. I haven't confused the two, just forgot to disable the nVidia RAID. Anyhow my final setup is WinXP on nVidia S-ATA Raid and OS X on Apple software raid, on two IDE ATA133 drives (only because I have a lot of Win software so I need to keep those 300+ GB Win accessible). For now OS X will have to cramp inside 74+ GB Apple raid. At least I'm satisfied with the results. The only annoyance that I have is every time I boot I have to bash F11 key to choose which system to boot. I'll be very thankful if you could recommend a boot-loader capable of booting GUID without having to install that Vista s**t just to get the BCD or even Linux for that matter, to use Grub.

I'm attaching a screenshot of Xbench score.