FWIW, when I pulled all of the suspension out of the 2005 SRT6 parts car I had, and went to move it to my limited, I found that the pad thicknesses were all different between the SRT6 and my 04 coupe. I remember looking at them and thinking that one end of the car was thicker on the SRT6 (front, I think) than the limited, and the rear end was the other way around. I wound up using all of the SRT6 stuff, and when it was done, the front end of the car sat very high, probably owing to the weight difference between the limited and the SRT6. Now that I have the V8, it sits lower than the SRT6 we have does, so that seems to confirm that.

Unsure why the parts catalogs show the same part number. When you have both sets of springs next to each other, it is immediately obvious that they are not the same.