I have a 26"-32" wedge ARE aluminum with standard rear door and tailgate. Also has side doors. The build quality is not up to the price of the topper. That said, I have had no issues and have flexed it plenty of times with lots of forest service road use also. It is mounted with 4 clam shell mounts, one in each corner. I wanted to put more and the dealer told me this would void the warranty. They said it is designed to flex and putting more mounts would negate the flexing.