The initial archive takes up very little space on your hard drive while transferring files or archiving them on external media. The Drawbacks
Yes, most highly compressed versions are identical to a standard installation in terms of game files. You should be able to install mods by placing them in the Documents\Euro Truck Simulator 2\mod folder. However, ensure your mods are compatible with version 1.30. Euro Truck Simulator 2 Version 1.30 Highly Compressed