Anyone know any good info on Software Raid performance and requirements of OS 10.2.1?

Finally got a new machine (Damn impressed by delivery speeds from G-mac. Machines released in US on Tues, had mine here on Fri) and looking into Striped Raid Array with some extra HD's before i start to install anything.

I'm gathering the Software raid gives improved HD access times at the expense of computer cycles? I can only find info on performance of softraid in OS9 and raid cards so far. I don't do any high level ripping or audio work though i'm more info graphic design and often work with very large files. Any recommendations. Assuming the hardware raid cards would take all the CPU performance loss on themselves relieving the CPU of that extra strain.

Plan is 2x 120gb on ATA 100 bus Striped Raid Array for the main work drive
2x 40gb on ATA 66 Striped array for the system and temp files and scratch disks

Can 10.2.1 run on a striped array without any problems?
Should the HD's be identical speced? The only 120g i can buy around is western digital whereas the internal one is IBM brand.

I'm gathering the drives should be as closed speced to each other as possible to stripe. I cant' get an IBM deskstar here but can get a 120GB westerdigital with 8meg cache.

Any help greatly appreciated or a direction to a page with good info would also be great.

Have yet to run the machine through its paces which i annoying with such a good machine just sitting here for now . Need HD sorted as soon as possible so i can go on an installation mission

Wes