what kind of filtration for a 180 gallon?

Hello,

I wanted to know what kind of filtration should i do with a 180 gallon tank? i am thinking something like this:

1) one 404 and one emperor 400

2) two-three emperor 400s

I dont know much about the 404's etc. do i have to drill a hole in the tank for the lines or what? Usually i only deal with power filters and not power heads and undergravel filters, so what should i do and how should i do it? Thanks in advance...