Although, I've seen the door tops lift as stated earlier (Goodwood races), my door structure must be pretty stiff as I have not witnessed any lift at up to 140+. My doors came with an inner door panel structure bonded to the outer skin, perhaps that delays the inevitable, but at our 75-80 mph speed limits here, the doors never move or lift.
As for weather seals, I use the McMaster-Carr supplied bulb seals around the door frame and replace them (8 ft each?) each year so they remain pliable and seal well. My tightest areas were along the A-pillar. As an alternative to using rubber seals, I did consider building a labyrinth type seal for the doors for sealing and as a water gutter to catch rain water and direct it downwards, however, it has been a non-issue as the bulb seal works quite well. For the front tires, I installed thick fiberglass sheet at the rear fender area (out of view) as a sort of inner fender/water blast shield. That stops about 70% of water splash, then a second wall of conformal neoprene foam (2" thick from McMaster-Carr) in front of the door hinge from top to bottom that conforms to the front of the door when it's closed shut, stops the rest.
For the sill area, a labyrinth type solution works using a flexible "skirt" seal attached to the underside inner structure (under door box) of the door. From my experience, that kept a good 90-95% of the moisture out after a downpour and driving 1-1.5 hr at highway speeds. Additional moisture seems to arrive in the cockpit as a mist or through the side window pop-outs and helicopter vents but that's manageable for me.