Porsche Tequipment Reveals Performance Roof Box Tested At Race Tracks May 12, 2021 at 8:56am ET ++ It is rated for speeds of up to 124 mph / 200 km/h and it also looks really cool atop a Taycan. Porsche markets all its vehicles as not only being very good to drive, but also practical and easy to live with. It is not at all uncommon to see a 911 sports car with a roof box and some even have cross rails on the back for additional storage, and now you can buy a roof box designed by the manufacturer to be safe at high speeds.