Is there literature that comes with it? I'm curious if there's a recommended maximum speed to be driving when you are opening it, or when it's already open.It's listed for $1,995 on the GMC Accessories site, but you save 20% when you spend over $500. I know we didn't pay $2K, but don't know how much since it was a birthday gift. I DO like it, now that I'm using it. On a sunny day, it's easy to flip open compared to removing the sky panels. I can open and close it from the driver's seat.