If it was a true progressive rate coil versus progressive wound there would be a difference compared to a linear rate coil but I am not aware of any true progressive rate coils for the TJ.
Since these are a set of Nth Degree springs, I have very little information about them. All I do know is free lengths matched up perfectly for my smaller tire build, but still allowed me to squeeze out 9" of travel front and rear. Not a lot by the standards of others, but the combination works extremely well for me now.