Buy from the Larian Vault if you want to help them the most. You don't have to worry about pre-orders that much in the digital era. Just buy and download!
Their next game that they plan on making in the future will most likely have a kickstarter at some point given the obvious success this one had. I peronsally check larian.com once a month and lar.net about every other week.
Since this game has an editor, it might keep the community from going dormant here between releases.
