Vanilla games treat cargo as static weight. In SLRR, cargo is physical objects. If you are transporting a bulldozer on a flatbed trailer on a ferry, that bulldozer has mass, can shift if you take a turn too fast, and must be secured with chains. This introduces an element of risk management absent from the base game.
To understand the significance of a mod pack, one must first understand the architecture of Street Legal Racing: Redline . Unlike modern racing games where customization is often skin-deep, SLRR allows players to disassemble engines down to the pistons, swap drivetrains, and adjust suspension geometry. A standard "mod pack" is essentially a curated archive that exploits this architecture. slrr mod pack