Silence in overflows is far less about how many pipes, and instead about how big your plumbing is. While I'm familiar with the Neo Nano, I can't honestly say that I know what size plumbing it uses. If its like all too many of the pre-drilled commercial tanks, its probably dual 1" drains. The idea is to provide as much potential flow rate to the sump -- your flow is 100% determined by the return from the sump, so having wider pipes just makes clogging and problems less likely.

If it were me/mine, I wouldn't mess with the plumbing -- the Neo Nano is such a pretty tank as it is, I'd be fearful of messing it up myself

-Justin