The rear coils on an R/T must be different then
I put a Ground Force 2/3 Drop on my RCSB 4x4 and the stock rear coils are standard, only the new replacement GF coils are progressive.
Good point. This could be a 4x4 vs 4x2 thing though also(meaning that it may be possible that a 4x2 single cab has progressive coils...maybe?). If one were to try to buy springs to cut they'd have to see them before buying them. I can say for sure the RT's will work as that's what I bought.