This is my friend FFS_Budman's site, which is a GREAT resource for NASCAR Heat! When DRT's site shut down, he put all of their files on his site, which is why I'm still making mods today. The DRT Mods are on the mods/other/DRT section.
If you want the Dev tools and templates, go here. If you're having trouble finding where the templates are, just search "templates" in the Ctrl+F search bar. Their template zip file contains a bunch of different templates for all of their default cars, even more than before. It even has the NSCR Stock Car templates which were formerly absent.
Where you can find Indiana Dirt Racing photos from 2006-2009 taken by former track photographer Jack Wart. They used to have 2003-2005 photos, but he got rid of those years, but a few can be found on Archive.org's Wayback machine.