System ?

I'm having some issues with my set-up so I am douching everything and doing a fresh install. I just want to confirm that this will be the best set-up. I just installed a second 160G sata in my G5 so. Main 160g Seagate SATA (OS & programs) Secondary 160 g Seagate SATA (gets all samples (Reason, DFHS, BFD, etc.) 200g Lacie firewire(800) as the audio drive. Is this the best set-up? I also have Logic 7 Pro, is there any special settings I need to make to get it to work with my 002r? I run dual G5 2.5ghz (10.3.4) 1.5g ram dual 160g sata drives 200g firewire drive 002r (6.4)

Also, I am new to Mac and never had to install an OS on Mac before. Is there a product number I will be asked to enter as you do with a PC when installing an OS? I have all the books with my G5 and don't see a number anywhere. I don't want to do a new install if it isn't going to work without the number. Is there a certain place where it would be?

no serial munber just run the install disc thats it for the mac os