The install is everything with the MX4. Tighten the rails from front to back pressing down firmly at each clamp point. Use equal torque on all the clamp bolts. Ensure the grooves on the clamps are seated in the grooves on the rails. When you put the cover on the rails pull it back until the bulkhead seal makes contact with lip under the front panel, but just touching, don't pull back hard. Check and recheck that the cover is square on the rails. That will take care of everything except for the leaking around the sides of the tailgate, but that is a tailgate issue not a cover issue. If you want to address the tailgate you can actually use strips of weather stripping to eliminate the vast majority of it. My truck just went through hurricane Irma and the bed is still dry except for a little water around the tailgate. I haven't done the weather stripping around the tailgate.