Replacement shocks for 67 GTS?

My 40+ year old Koni's on the rear are starting to leak. They are standard adjustable ones and I like the way they ride but they don't make them anymore and for Koni to rebuild them is ~$200 each for the rears. So what else can I get that will ride like them and not cost so much.

They aren't gas charged and I think these Koni's only dampen one way. I had some SS springs on once with them. I tried the Mopar gas shocks that were suppose to be make to work with the SS springs and I didn't like them at all. They were gas shocks. I went back to stock springs with the Koni's. Street car only.