I'm fitting pop-out quarter windows to a '79 SC. I've done my research, and done each step very precisely. Everything was going pretty well until I started fitting the seal to the glass. The smaller one between the glass and the inside of the frame. I got them on the glass and in the frame fairly easily, but then when it came time to fasten the straight section of the frame, it took two guys squeezing and pushing, and some clever loosening and tightening of the tiny screws at the corner to get the frame to assemble. Both were an incredibly tight fit. I followed up by fitting the larger seal to the outside of the frame. That went well. On to fitting the windows in the car I ran into a problem. The windows wouldn't fit. They would close just a little, then stop midwat towards the back of the car. Sighting from the front towards the latch end, I could see that the window frame was making contact about midway--the front by the B pillar and the latch end looked pretty good, it was just the middle that was hanging up. I lubed the rubber a little, and that helped a bit, but it was clear that the frame was simply too large for the opening. Took the frame out of the car and placed a clamp across the frame (top to bottom) about where it was binding. I put some tape on the glass to monitor the movement. With a squeeze I could compress the frame at least 1/8". I had the idea that since the end piece was so difficult to install, that the seal might be too large. Thus, the clamp squeezed the seal and allowed the frame to "get smaller". So I took and extra seal I had bought (it's unbranded--not labelled official Porsche) and compared it to a seal from an old window I had. I was surprised to see that the old seal, although shrunk with age and hard, was dramatically smaller and thinner than the new seal. See the pic below. The old seal is on top. I know it doesn't look terribly different, but the new seal is just so thick and tall. This is a side view, so the glass would insert from the top (in the direction of the red arrow). I'm now thinking that these seals are way too large, and are expanding the frame to the point that it won't fit in the car. I don't have experience with these seals, so if anyone can offer some experience here, I'd appreciate it.