I bought a set a while ago and have never really been happy with them, mainly where the screws go in on either end, it seems the once you put the screw though the seal to the car and but a bit of tension on it pops off, even with a washer on it still does it now the connectors around the seal are popping off seems the rubber is too soft.
Have i bought the cheap set? or just a bad set any advice would be great as now looking for a more solid set

 

the original GM seals had a plastic insert that kept things a bit more sturdy around that screw. unfortunately most of the aftermarket ones do not. if you're having issues keeping that section in place, it may help to put a dab of weatherstrip adhesive between the seal and the door panel and then install the screw to keep things in place while curing.