Dimension 9200 Adding Sata drives

i have a Dimension 9200 . Its has 2 x 160gig HDD in raid 0. I would like to add some more sata drives internally. I spoke with tech support and was told while there are 3 spare sockets on the motherboard there is no space to place the drives. Of course you can place the drives with a bracket under the dvrom. The issue then turned to the raid 0 configuration of the existing drives.

I have upgraded the psu due to a new graf card so have plenty of sata power connectors

By adding these addition drives could you setup as a completely seperate partition leaving the existing raid setup alone so not to loose the excisting data?

In the bios you can create a new raid seperate to the existing one (i assume) and the os should detect this as a seperate drive?

Thanks