I've seen "Dr. Vinyl" do very good repairs on cracked/torn Tex.
I took my C230 into an automotive upholstery shop this morning. They took out the seat, took the bottom Tex off, fixed the offending piece and checked the rest of the material. He reinforced the worn part and restitched the seam. Then reinstalled the seat.
Total cost: $220.
The fix looks great, and the seat looks like new again. While I am happy now, it still worries me that the quality of the material has fallen.
1998 C230 "Black Betty"