This is the 2020 Serpent Opus 350-HD, a long and wide pickup truck designed for tough hauling. It's got wide rear tires and stiff rear springs to handle heavy loads, but it's also got room for five and is comfortable to drive.
It's both longer and heavier than the Opus 250, and as such is fitted with a more powerful version of the turbocharged 6.5L engine - now producing 400 horsepower at the crank.
The rear suspension bottoms out quite easily. This is the fault of the body used, so I can't do anything about that. Let me know if there's anything else though.
The 1.1 update version of the Opus in-game.