FYI - I'm using their sway bars on my 1970 Skylark Custom convertible. Very happy with the product. They are having a sale over Thanksgiving. https://www.spohn.net/
I have all Spohn suspension on the rear of my car, their products are nice but their customer service is pretty horrible.
Yea they are pretty hard headed for sure...I informed them their rear anti roll bar legs were 2in to long.....they said my car was 2in too short???
I believe they started with third-gen F body stuff. It was a son and father business out of Pa. I liked giving them business. I've bought plenty from them and never had an issue, but also never needed to call tech support either.