im not 100% but i know that i have herd that it is not a DIRECT replacement, as other parts are nessicary.

i know that the control arms on a 97-03 are different then the 04+, so if you are using an 04+ cradel, you WILL need 04+ control arms.

i am not sure about using an impala cradel though. the stock control arms may bolt right up, but im not sure