My plan, though I haven't tried it yet, was to line the recessed parts on my scirocco rear side panels with several layers of plastic film taped as well as possible to the recessed bit. Then fill it with spray foam and cover that with plastic and a board pressed with a heavy weight or clamp. Once dry, this would create a reverse mold of the recessed part that would be very firm. Then I was going to glue the vinyl to the card and using the reverse mold to push it in equally until the glue sets. More on reddit.com

If it were me, I would just ditch the styrofoam. I would imagine that the styrofoam is probably there mostly for noise reduction, but since it is thin I don't think it will cause much of a difference, if at all. I had a similar experience with a door panel, but instead of leather and styrofoam it was carpet and plastic. The carpet was originally glued to the plastic but once it peeled away, it would no longer adhere properly, regardless of adhesive. Once I ditched the plastic, the carpet stuck quite well. More on reddit.com

I agree completely. I attempted the headliner in my 99 M3 before getting a quote at a local shop for $500. Well worth the money. Came out way better than I could have done. More on reddit.com

cechaflo in youtube he makes everything look simple. its not overly hard, very time consuming, but worth it on so many levels More on reddit.com