What is the difference between container shipping and RoRo for JDM imports?

RoRo (Roll-on/Roll-off) is cheaper ($800-$1,400) and involves driving the car onto a cargo ship. Containers ($1,500-$3,500) place one or two cars in an enclosed metal box. RoRo exposes the car to salt air and weather; containers offer better protection for low-slung sports cars. Most importers prefer containers for high-value or low-clearance vehicles. Both typically take 4-6 weeks port-to-port from Japan to the US West Coast.