You can often find the original disc images (ISOs) on the Internet Archive , which can be mounted as virtual drives.
Some community-curated versions come pre-packaged with all DLCs and basic compatibility fixes. Essential Community Mods & Fixes
When downloading from unofficial sources or using community cracks, your antivirus may flag files as a "false positive" because the original executable has been modified. Always ensure you are downloading from reputable community hubs like TurboDuck or well-moderated subreddits.
Are you planning to install the for the extra cars, or
Since original authentication servers are down, most downloads include a modified .exe to allow offline play. Important Security Note
To run TDU1 smoothly on modern Windows systems, you will likely need a few additional files: