Ive noticed the rear seal on the tailgate isnt real tight, but I can live with it. I haven't driven it in a hard rain yet. I might try scooting it back a little. Going through the car wash let in a little water but nothing that didnt dry quickly. I also bought an access LED light kit and the tailgate seal kit when I got mine. I ran a wire from the battery along the frame rail.
Oh and yes my bed mat doesn't fit (yet) It came out of my Sierra Crew. I wasnt gonna give it to the dealer when I turned it in.