Mines drilled in the top back with the overflow box in the tank. I also have a sump....maybe I should just upgrade the size of my sump then if theres not to much difference. It's quite tight with the live rock, drain pipe, protein skimmer and return pump. It's only a 24 inch sump I believe. Problem is, how to get a bigger sump in without having to take the tank off.....

Anyway, I know it was kinda a dumb question, was just curious if there was much of a difference.