As topic says, would they fit and what would be needed to change/adapt to get em fitted into a superb? Why am I asking? I am experiencing some massive lower back pain when going on longer drives with my superb mk2 facelift, I've got the electrical 12-way all leather ones with lumbar support but I must say that I do not like the ride at all and thought that hey, maybe the passat ones would fit bolt on since it's pretty much the same car?

I doubt it has been tried. I am not sure they would fit. As I recall, the superb is noticeably wider than the Passat. I also remember my Passat seats giving my a lot of issues with my lower back. The Superb is better for me in that respect.

Also had a log of issue with my legs in the passat.

 

Maybe you should consider going to various dealers with superbs and trying the seats. If they feel better, I guess you would have a much easier time swapping for another superb seat.

If you're having issues with seat adjustment, try resetting everything to its lowest position, and start again. I have lower back issues and once I got the seats properly adjusted they've been great over long journeys. One adjustment I found particularly good for my back was to tilt up the front edge of the seat base a little so that my thighs were fully supported.