I have 4" TC EZ-HD's. I know that they are the HD's but they are stiff even with 180lbs or winch & bumper up front. They broke in after several hard wheeling trips but they are still not soft IMO. I believe that Matt's (az-k5) BDS springs are every bit as soft or softer then my TC HD's.
I have TC's now that need to be replaced & when I replace them I will use BDS for sure.
Harley