Sump questions, what are the benifits?

[RDavies]

I have my 6x2x1.5 tank with an Aqua One 2400 canister filter, starting to fairly well planted. After looking at JTs set up I have been thinking about sumps. Will running a sump in my cabinet be of any benefit to me? My tank doesnt have extra holes in the back or anything, are these needed to run a sump?

[ILLUSN]

You dont need holes, you can use an overflow box for a sump, sumps have massive media capacity, add extra volume to your tank and are a nice place to hide co2 reactors, heaters etc