I should know this I just had to drill out the two on each side in order to mount the mirror adapters to go topless. Yeah drill... they would not come out with the torx - just striped the torx head. I threw the baggie away but going from memory they were 5/16-18 and length was an inch - double check me.
Ya....... 5/16 coarse thread about an inch long, but length isn't real critical as there is a lot of room behind the threads, there usually tight as there lock tited from the factory so some heat would help except in the rust belt areas.
My Jeep is NOT an suv and Your suv is NOT a Jeep