the one thing you want to be careful of with rims is that you get the correct bolt pattern. the 00-05 bolt pattern is 5x115mm. i believe the newer impalas are the same. ford mustang rims will "fit" but not correctly. the bolt pattern on those is 5x114.3 so dont let anyone tell you they work. they dont. you will eventually break off a wheel stud and thats bad business. as far as the CTS rims go, since ive done all this talking, to answer your question, yes they should fit since the bolt pattern ive found for an 05 cts is 5x115. you may want to check back spacing and that type of thing as i think the CTS may be rear drive compared to our front drive impalas.