Yesterday I took my headliner to a local automotive upholstery company I've used in the past...
Met with the owner of
Tritex Corp. and he had the perfect fabric match and has done a number of Cayman headliners...
Normally he charges $750 + tax, but since I had already pulled the headliner from the car, the estimate became $300 + tax...
I was concerned with attempting this myself mainly due to the deep contours and the possibility of getting wrinkles...
That and the problem with contact adhesive only giving you one shot to get it right... I decided to let the expert do it....
This is what he uses...

I gave him the headliner at 1:00pm yesterday and I got a text at 8:00am this morning that my order was ready for pickup...
I'm impressed, less than 24 hr turnaround...
Finished headliner...
I added painters tape and laid a blanket over the dash to protect from any possible scratches...

Completed the install at 3:00pm today, and didn't break any plastic tabs...
All in all, I saved about $2,300 doing it myself vs the dealer...
As a side note, the owner had a 3D printer out in the shop to replicate plastic fittings / clips that are no longer available...
He recreates broken parts as needed when he's doing a job...