hm didnt think about that kinda scares me to drill the 40 though never done it.. my other tank came pre drilled lol guess there is a first for everything
LOL .. Well that was info I didnt have
you could always drill the 40g and pick up a 20g (pretty cheap) for the sump. Or you could use a overflow for the 40g. Drilling would be better.
Just think it through and decide what would be best for you. Since it's not set up yet, now is the time to design it correctly. It will save a lot of headache and make the experience a lot more enjoyable.
I myself have a lot of "I wish I would have done it differently" moments