[bighap]

I don't know a whole lot about hardware, but you generally have primary master, primary slave, secondary master, and secondary slave. So you have the two masters for your two hard drives and the two slaves for two burners. I don't know how you go about getting two more burners in there. I know they have large duplication towers though, so it can be done but I am not sure how. Sorry I am not of more help. Maybe someone with a better hardware background will know.