Scania DC16 V8 & Opticruise G-Box Revision for R/S NG

This overhaul replaces the default engine and gearbox logic in the Scania R/S NG to match real-world performance. The DC16 V8 lineup (590, 660, and 770 hp) now features a 550 RPM idle and 2000 RPM rev limits, with tuned shift points that leverage the engine's massive low-end torque. You'll notice smooth 13th gear engagement at highway speeds and realistic engine braking for better cooling. The Opticruise G-series gearbox also gets a proper retarder system with five distinct steps, progressively combining retarder and engine brake power while triggering automatic downshifts at higher levels. A huge quality-of-life update for anyone who wants their Scania to feel authentic on the road.