Depends on how much you hold grudges and how much you will go through to hurt somebody who has hurt you.
If you can't really be bothered to do much I'd suggest you, as the builder just post the project here for everyone to download for free. That way the server owner who used to have a stolen $10 spawn now has a free open-source build.
If you want him to suffer you could join on an alt account and over the course of a month or so, gain trust and try to get a staff rank.
If by the small chance it's running on his home computer, with a router than can only handle so much traffic there's something that I won't openly condone but it's still an option and is easier than gaining his trust.
Best of luck.
