With GPA closing, recone by them may be up in the air. Too bad, because they have or had the only correct cone kits.
Aftermarket kits are available, I reconed two I have myself. The aftermarket spiders are much stiffer than the originals. Fs of the two I did came out to 35hz vs the factory parts that are closer to 20hz.
They work great, but don’t meet factory specs. They look different to boot.

This won’t let me upload a photo sadly