The vehicle you are describing, the small construction roller priced at $10,000 with a top speed of 8 mph downhill and potentially 9 mph if luck is on your side, sounds like an interesting addition to FS25! The choice of the John Deere 3650 engine sound is a nice touch and adds to the realism of the vehicle. It seems like a practical and affordable option for construction and land preparation tasks within the game. The modest top speed reflects the nature of a construction roller, which is typically designed for effectiveness rather than speed. Overall, this vehicle would likely appeal to players looking for a reliable and realistic construction roller in the game.